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STUDENTS’ MISCONCEPTIONS ABOUT CELL BIOLOGY AND CELL DIVISION: THE CASE OF KELAFO SECONDARY AND PREPARATORY SCHOOL, SOMALI REGION, ETHIOPIA M.Ed Thesis GETNET HAILEGEBRIEL October, 2014 Haramaya University STUDENTS’ MISCONCEPTIONS ABOUT CELL BIOLOGY AND CELL DIVISION: THE CASE OF KELAFO SECONDARY AND PREPARATORY SCHOOL, SOMALI REGION, ETHIOPIA A Thesis Submitted to the College of Natural and Computational Sciences, Department of Biology, School of Graduate Studies, HARAMAYA UNIVERSITY In Partial Fulfillment of the Requirements for the Degree of MASTER OF EDUCATION IN BIOLOGY By Getnet Hailegebriel October, 2014 Haramaya University ii SCHOOL OF GRADUATE STUDIES HARAMAYA UNIVERSITY As thesis research advisor, I hereby certify that I have read and evaluated this thesis prepared under our guidance by Getnet Hailegebriel, entitled “STUDENTS’ MISCONCEPTION ABOUT CELL BIOLOGY AND CELL DIVISION: THE CASE OF KELAFO SECONDARY AND PREPARATORY SCHOOL, SOMALI REGION, ETHIOPIA”. I recommended that it be submitted as fulfilling the Thesis requirement. Sissay Menkir (PhD) Advisor ______________________ Signature ____________________ Date As member of the board of examiners of the M.Ed Thesis Open Defense Examination, we certify that we have read and evaluated the thesis prepared by Getnet Hailegebriel and examined the candidate. We recommended that the thesis be accepted as fulfilling the thesis requirements for the degree of Master of Education in Biology. ___________________ Chairman ____________________ Internal Examiner ____________________ External Examiner _____________________ Signature _____________________ signature ______________________ Signature iii __________________ Date __________________ Date __________________ Date DEDICATION I dedicated this thesis work to my beloved families and friends who provided me with love and support throughout my studies. iv STATEMENT OF THE AUTHOR First, I declare that this thesis is my original work that all sources of materials used for this thesis have been duly acknowledged. This thesis has been submitted in partial fulfillment of the requirements for M.Ed. degree in biology at the Haramaya University and deposited at the University Library to be made available to borrowers under rules of the Library. I solemnly declare that this thesis is not submitted to any other institution anywhere for the award of any academic degree, diploma or certificate. Brief quotations from this thesis are allowable without special permission provided that accurate acknowledgement of source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the head of the major department or the Dean of the School of Graduate Studies when in his or her judgment the proposed use of the material is in the interests of scholarship. In all other instances, however, permission must be obtained from the author. Name: Getnet Hailegebriel Signature _____________ Place: Haramaya University, Haramaya Date of Submission: August, 2014 v BIOGRAPHICAL SKETCH The author was born in 1986 in Sheno town, North Shoa Zone. He attended his Elementary Education at Sheno Elementary School and secondary education at Sheno Secondary School. He joined Addis Ababa University in 2007 and graduated with B.Ed degree in Biology in 2009. Upon his graduation, he has been employed by Ethiopian Somali Region Education Bureau and worked as biology teacher in Gode zone, at Kelafo Secondary and Preparatory School. In 2010, he joined the School of Graduate Studies of Haramaya University in Summer (Kiremt) Program in College of Natural and Computational Sciences, Biology Department to pursue Master of Education in Biology. vi ACKNOWLEDGEMENTS I would like to thank my advisor Dr. Sissay Menkir for his precious assistances and professional guidance. I have received his assistances during my proposal formulation and preparation of the thesis. I also would like to thank Biology Department of Haramaya University. I also thank biology teachers of Kelafo Secondary and Preparatory School for their extensive help during the study. Indeed, my thank goes to students who were participated in this study. I would like to express my heartfelt thanks to my families and to all my friends for providing me moral support, encouragement and financial support when I most need it. vii LIST OF ABBREVIATIONS AND ACRONYMS AAAS American Association for the Advancement of Science CSA Central Statistical Agency KSPS Kelafo Secondary and Preparatory School NEA National Education Association NCERT National Council of Educational Research and Training TTDT Two Tier-Diagnostic Test VSLB Virginia Standards of Learning for Biology viii TABLE OF CONTENTS STATEMENT OF THE AUTHOR V BIOGRAPHICAL SKETCH VI ACKNOWLEDGEMENTS VII LIST OF ABBREVIATIONS AND ACRONYMS TABLE OF CONTENTS VIII IX LIST OF TABLES XII ABSTRACT XIII 1. INTRODUCTION 1 1.1. Background of the Study 1 1.2. Statement of the Problem 2 1.3. Research Questions 2 1.4. Objectives of the Study 3 1.4.1. General Objective 3 1.4.2. Specific Objectives 3 1.5. Significance of the Study 4 1.6. Delimitations of the Study 4 1.7. Limitations of the Study 4 1.8. Operational Definition of Key Terms 4 1.9. Study Period 5 2. REVIEW OF RELATED LITERATURE 6 2.1. The concept of Misconceptions 6 2.2. Sources of Misconceptions 7 2.3. Common Misconceptions in Biology 9 2.4. Methodologies for Investigating Students‟ Misconceptions in Biology 13 2.4.1. Interviews 14 2.4.2. Multiple Choice Tests 15 2.4.3. TTDT 17 2.5. Methods of Removing Students‟ Misconceptions 18 ix 3. RESEARCH METHODOLOGY 21 3.1. Description of the Study Area 21 3.2. Research Design 21 3.3. Study Population, Samples and Sampling Procedures 21 3.4. Data Collecting Tools 22 3.4.1. Document Analysis 22 3.4.2. Interview guide 23 3.4.3. Questionnaires 23 3.4.4. TTDT of Cell Biology and Cell Division 24 3.4.5. Classroom Observations 24 3.4.6. Procedures of Data Collection 25 3.5. Methods of Data Analysis 25 4. RESULTS AND DISCUSSIONS 26 4.1. Identified Key Concepts and Propositional Knowledge Statements about Cell Biology and Cell Division 26 4.2. Assessment of Students‟ Misconception about Cell Biology and Cell Division 29 4.2.1. Students‟ Misconception Identified by Interview 30 4.2.2. Students‟ Misconception Identified by Questionnaires 32 4.2.3. Students‟ Misconception Identified by TTDT Items 33 4.3. Observed Misconception Held by Students about Cell Biology and Cell Division 38 4.4. Level of Students‟ Misconception about Cell Biology and Cell Division 40 4.5. Common Sources of Students‟ Misconception about Cell Biology and Cell Division 41 4.6. Evaluation of Teachers‟ Instructional Methods Used to Remediate Students‟ Misconception about Cell Biology and Cell Division 42 5. SUMMARY, CONCLUSION AND RECOMMENDATIONS 44 5.1. Summary 44 5.2. Conclusions 45 5.3. Recommendations 46 6. REFERENCES 47 7. APPENDICES 55 7.1. Appendix I. TTDT 55 x 7.2. Appendix II. Questions for Interview 58 7.3. Appendix III. Open-ended Questionnaires 59 7.4. Appendix IV. Close-ended Questionnaires 61 7.5. Appendix V. Cell Biology and Cell division Diagnostic Test 62 7.6. Appendix VI. Classroom Observation Checklist 67 7.7. Appendix VII. Target Concept and Propositional Statements of Cell Biology and Cell Division 69 7.8. Appendix VIII. Response of Students for Interview Questions 73 7.9. Appendix IX. Response of Students for Open-ended Questionnaires 77 xi LIST OF TABLES Table Page 1 Students‟ sample size 2 Summary of key concepts and their propositional knowledge statements that are included in grade 10 biology textbook and syllabus related to understand cell 26 division. 3 Summary of key concepts and their propositional knowledge statements that are included in grade 11 biology textbook and syllabus to understand cell biology. 4 5 6 7 8 9 22 Summary of grade 10 and 11 students‟ misconception about cell biology and cell division of TTDT. Frequency of students‟ response categories for interview questions about their prior conceptions of cell biology and cell division. Frequency of students‟ response categories for open-ended questionnaires regarding their prior conceptions of cell biology and cell division. Frequency of students‟ response categories for TTDT items regarding their understanding of cell biology and cell division. Common misconceptions identified about cell biology and cell division in grade 10 and 11 students at KSPS. Criteria to analyze the cell biology and cell division diagnostic test items based on students‟ response. 10 Sources of Students‟ misconception as reported by teachers for close-ended question categories about cell biology and cell division. xii 27 29 31 32 34 39 40 41 STUDENTS’ MISCONCEPTIONS ABOUT CELL BIOLOGY AND CELL DIVISION: THE CASE OF KELAFO SECONDARY AND PREPARATORY SCHOOL, SOMALI REGION, ETHIOPIA Getnet Hailegebriel Advisor - Sissay Menkir (PhD) ABSTRACT The purpose of this study was to identify grades 10 and 11 students’ misconceptions about cell biology and cell division, their sources and levels and to evaluate the effectiveness of biology teachers’ instructional methods to remediate students’ misconception. The study was carried out at KSPS, Somali Region, Ethiopia. The TTDT of cell biology and cell division was prepared and administered to 120 grade 10 and 11 students after their prior conceptions about the selected topics of the study were collected from students through interview and open-ended questionnaires. Three biology teachers were observed in classroom using observation checklist while they were teaching different topics of cell biology and cell division. A mixed probe design was employed in this research. The researcher has identified two key concepts and 22 prepositional knowledge statements related to cell division, and three key concepts and 24 prepositional knowledge statements related to cell biology of grade 10 and 11 biology, respectively. The result revealed the existence of students’ (grade 10 and 11) misconception about cell biology and cell division with average value of reliability coefficient, discrimination indices and difficulty indices of 0.58, 0.41 and 0.37, respectively. The results also revealed that biology text books, teachers’ English language skills and biology instructional methods were the major source of students’ misconception about cell biology and cell division. The result showed that the majority of the students’ had high level of misconception about cell biology and cell division. The result showed 16 types of common misconceptions about cell biology and cell division, which were categorized into: definition of cell biology and cell division, structures and functions, types, energy and cell cycles. Moreover, the observed classes of cell biology and cell division lessons showed that all biology teachers did not implement effective instructional methods to remediate students’ misconceptions. Educational curriculum designers and stakeholders need to design the educational materials including biology text books and continuous educational supervisions and on-job trainings for school biology teachers as well as fulfillment of the required educational facilities are recommended by the researcher. Keywords: Cell biology, Cell division, Misconception, TTDT. xiii 1. INTRODUCTION 1.1. Background of the Study Human beings can learn and explore the horizons of the universe and create knowledge. The human basic knowledge can be acquired through logic and observation which is further refined into scientific knowledge. Beginning with the work of Piaget in the 1920s to the present time, enormous studies have been done on science education focusing on identifying, analyzing, understanding and mapping the concept students held before and after instruction (Wanderse, 1994). Identifying students‟ concepts (prior knowledge) is a major area of science education research. Mental representations of a given concept which is different for the currently held scientific theories is termed as misconception (Kesidou and Duit, 1993; Lewis and Linn, 1994) which can be distinguished into two kinds: (a) alternative or experiential or intuitive or native conceptions and (b) instructional misconception (Skelly and Hall, 1993; Nakiboglu, 2003). Over the past three decades there have been growing international interest in studying the ways in which learners view the natural world and their resulting conception. Studies in science education have been focusing on identifying and analyzing the idea and concepts students held before and after instruction. Most of the studies have confirmed the students usually bring in science education ideas that differ from those held by the instructors and accepted as correct by scientific community. Such views of students have been variously described by different researchers. For example, alternative conception (Driver and Easley, 1978) and misconception (Fisher, 1985). Misconceptions have serious impact on students‟ learning. The occurrence of these misconceptions hinders students from learning concepts that are more advanced. When students‟ initial understanding is not carefully considered, they may fail to grasp new concepts and information presented in the classroom, or they may learn for the purpose of test but revert to their misconceptions outside classroom (Ozmen, 2004). It is important that the biology teachers find ways to identify and carefully address those misconceptions that students bring to the classroom. 1 Misconceptions that already exist in learners‟ mind are considered as barriers in understanding biological sciences and they adversely affect subsequent learning. Recent studies on students‟ conceptual understanding of fundamental concepts in life science have indicated that new concepts can hardly be learned unless the existing misconception is corrected or students are made to bring conceptual change. However, before misconception can be corrected, they need to be identified. It is a well known fact that students enter in biology classroom with a lot of misconceptions which are based on their beliefs and observations. In Ethiopia only few attempts have been made to identify students‟ misconception in physical and life sciences, such as biology, physics, chemistry and mathematics (Temechegn, 2002). The researcher temechegn has investigated on primary and secondary school teachers‟ alternative conceptions about structural models and fourth year Addis Ababa University students understanding of basic concepts of solid-state chemistry. 1.2. Statement of the Problem This research would be an investigation of existing misconceptions that conflict with currently accepted scientific concepts in students studying about cell biology and cell division at KSPS. There was no any research have been done on students‟ misconceptions in biology and other subjects at KSPS. In this study to address students‟ misconceptions and identified the common misconceptions previously held by students at KSPS. Therefore, the purpose of this research was to identify grade 10 and 11 students‟ misconception about cell biology and cell division using TTDT, identify the target concepts and propositional knowledge statements, sources of students‟ misconception, level of students‟ misconception and to evaluate the effectiveness of biology teachers‟ instructional methods to remediate students‟ misconception at KSPS, Ethiopian Somali regional state, eastern Ethiopia. 1.3. Research Questions 1. What were the identified target concepts and propositional knowledge statements necessary for grade 10 and 11 students to understand the topics of cell biology and cell division? 2. What were the common misconceptions held by grade 10 and 11 students about cell biology and cell division at KSPS? 2 3. What were the sources of grade 10 and 11 students‟ misconception about cell biology and cell division at KSPS? 4. What was the level of grade 10 and 11 students‟ misconception about cell biology and cell division held at KSPS? 5. Are the instructional methods practiced by biology teachers effective enough to remediate students‟ misconceptions about cell biology and cell division at KSPS? 1.4. Objectives of the Study 1.4.1. General Objective The main objective of this study was to identify grade 10 and 11 students‟ misconception about cell biology and cell division using TTDT, identify the target concepts and propositional knowledge statements, sources of students‟ misconception, level of students‟ misconception and to evaluate the effectiveness of biology teachers‟ instructional methods to remediate students‟ misconception at KSPS. 1.4.2. Specific Objectives The specific objectives of the present study were to: 1. Identify the target concepts and propositional knowledge statements necessary for grade 10 and 11 students to understand cell biology and cell division at KSPS. 2. Identify common misconceptions about cell biology and cell division held by grade 10 and 11 students at KSPS. 3. Assess the sources of students‟ misconception about cell biology and cell division at KSPS. 4. Assess the level of students‟ misconception about cell biology and cell division at KSPS. 5. Evaluate the effectiveness of grade 10 and 11 biology teachers‟ methods of instruction about cell biology and cell division to remediate students‟ misconception at KSPS. 3 1.5. Significance of the Study Information about the development of misconceptions was particularly useful for science teaching community in order to develop curriculum materials and design instruction. Therefore, this study was significant in helping teachers and curriculum developers to address and design teaching and learning process. It was also used as a starting point for the development of subsequent learning activities based on some common and key misconceptions. Moreover, this study lays a foundation for future studies that aim to investigate it the causes of misconceptions and appropriate to bring conceptual change and develop problem solving skill. 1.6. Delimitations of the Study The primer concern of this study was to identify students‟ misconception about cell biology and cell division at KSPS the key factors that significantly affects students‟ misconception. The study was confined in KSPS, kelafo wereda, Gode Zone, Somali National Regional State, would be addressed. It is assumed that the findings of the study would be sound enough in addressing the problems of students‟ misconception at KSPS. 1.7. Limitations of the Study The results and conclusions generated in this study refer specifically to the sample groups involved in the study. Generalization of the findings to all students in Gode Zone must be considered with caution due to the nature of environment and the limited size of the sample. Students may not understand or may misinterpret the questions and options in the cell biology and cell division diagnostic test, and since they are commonly familiar with the normal traditional multiple choice types of test items that have only one part, this may affect the validity and reliability of the test. 1.8. Operational Definition of Key Terms Concept is an abstract or general idea inferred or derived from specific instances Misconception is a belief that contradicts accepted scientific theory. Conception is the power of recalling a past sensation or perception 4 Diagnostic tests are a test with items in multiple-choice or short answer format that has been designed with common misconceptions Statement of proposition is two more concepts are linked by word (s) to describe the relation between the concepts. 1.9. Study Period Interview questions about their prior conceptions of cell biology and cell division, in grade 10 and 11 students at KSPS, were distributed during December, 2013; Open-ended questionnaires were distributed during January, 2014 and TTDT were distributed during February, 2014. 5 2. REVIEW OF RELATED LITERATURE 2.1. The concept of Misconceptions In broad terms, misconception corresponds to the concepts that have peculiar interpretations and meanings in students‟ articulations that are not scientifically accurate. In the literature misconception are also referred to as naive beliefs (Caramazza, McCloskey and Green, 1980), erroneous ideas (Fisher, 1985), preconceptions (Hashweh, 1988), multiple private versions of science (McClelland, 1984), underlying sources of error (Fisher and Lipson, 1986), personal models of reality (Champagne, Gunstone and Klopfer, 1983), spontaneous reasoning (Viennot, 1979), persistent pitfalls (Meyer, 1987), alternative frameworks (Driver and Easley, 1978) and children science (Gilbert, Watt and Osborne, 1982). Although the term misconception is dominant in the literature, some researchers (Abimbola, 1988; Gilbert and Swift, 1985 and Wandersee, Mintzes and Novak, 1994) now prefer the term alternative conception. It is important to use the term misconception rather than the alternatives in order not to create concept confusion because of the following reasons. It is still commonly used by many researchers, the term already has familiarity in the public and it easily conveys the message that a concept might have contradictory connotations with the current scientific thought in science education. The term concept does not have a standard meaning but the researcher was accepted this definition for his research. Concepts can be considered as ideas, objects or events that help us understand the world around us (Eggen and Kauchak, 2004). Concept is an explanatory principle in a scientific system also called conception the interpretation and explanation given by the student will exhibit his or her concept about the specific term (Voska and Heikkinen, 2000). A conception is an idea or notion. The ideas, notions and understandings about a specific topic or subject that students possess prior to formal instruction are considered preconceptions (Brown, 1994). Misconception on the other hand can be described as ideas that provide an incorrect understanding of such ideas, objects and events that are constructed based on a person‟s experience (Martin et al., 2002) including such things as preconceived notions, non-scientific beliefs, naive theories, mixed conceptions or conceptual misunderstandings. Research into conceptions held by students has shown that there can be 6 significant differences between the same phenomena even after formal instruction, this is refereed as misconception. Children assemble their thoughts about how the world works and explain scientific phenomena in terms of their thoughts. These kinds of ideas are referred as misconception or alternative conceptions (Canpolat, Nurtac and Pnarba et al., 2006). Nakhleh (1992) defines misconception as concepts which students construct on their own but these are outside the concepts which are scientifically accepted or are aimed to be constructed by teachers. Main reasons for misconception are faulty or insufficient perception of the concepts learnt, concepts of daily language having different meanings in scientific language, not using appropriate teaching approaches while teaching topics and concepts, insufficiency in the construction of relationships between the concepts and concepts and daily life (Mann and Treagust, 1998). The big issues are that once a misconception has been formed it is extremely difficult to change (Eggen and Kauchak, 2004) and that possessing misconception can have serious impacts on learning (Hanuscin, 2005). Students come into the classroom with prerequisite knowledge or existing schemas and as they progress through their education these schemas are progressively or sequentially built upon (Alagumalai, 2005). 2.2. Sources of Misconceptions A search of related literature reveals that textbooks, reference books, teachers, language, cultural beliefs and practices are some of the principal sources of high school students‟ misconception of many science concepts including those in biology. There are many possible sources for the development of misconception. First, not all experiences lead to correct conclusions or result in students seeing all possible outcomes. Second, when parents or other family members are confronted with questions from their children rather that admitting to not knowing the answer it is common for them to give an incorrect one (Alagumalal, 2005). Textbook is one of the sources of misconception. It is a tool used in the teaching-learning process and is the guide for teachers and students. It is the tool to show the scope and limitations of the curriculum and a major resource in school sciences. The textbook is usually regarded by educators throughout the world as a good source of information for teaching. Abimbola and Baba (1996) stated that American biology teachers rely solely on textbooks for use in their instruction. According to them “nearly 90% of teachers use a textbook 90% of the 7 time”. In India too, science teachers rely solely on textbooks for the appropriate content materials that satisfy the requirements of the science syllabus and the national curricula in the different science subjects. Textbooks are perhaps the only learning materials available and used in most Indian schools. The textbook as a tool of instruction has great significance in learning because it presents a treasure of knowledge to students and also creates real interest for subjects. If the instructional material contains any defective knowledge or information the consequences will be serious for students and hence for the whole country. In India most textbooks are prepared by the government bodies such as the National Council of Educational Research and Training (NCERT) (2006) and are used all over the country for central schools or by the state bureaus of textbook production and curriculum research for use in state schools. Teachers as a source of misconception studies provide valuable information regarding awareness of and struggle with misconception there are not enough studies regarding teachers‟ attitudes towards misconception such as teachers‟ general perceptions of misconception or how much importance they give to students‟ misconception during their teaching. In fact, teachers‟ attitudes may affect their teaching process in the lessons and the environment they create for students‟ meaningful learning. As for science lessons (Huinker and Madison, 1997) stated those teachers‟ attitudes and beliefs about science and science education play an important role in the way their behaviors in science teaching take shape. It is expected that understanding teachers‟ attitudes towards students‟ misconception provide useful information to teacher educators, curriculum developers, textbook writers and teachers in their struggle with students‟ misconception. Other sources of misconception include reference books, language, cultural beliefs and practices. The main issue is that all of the above sources are considered to be trustworthy leading to ready acceptance by students of what they are being taught. 8 2.3. Common Misconceptions in Biology To date, several studies have investigated students' understanding of biological concepts in different countries. Cell (Dreyfus and Jungwirth, 1988), photosynthesis (Bell, 1985, Haslam and Treagust, 1987, Waheed and Lucas, 1992), respiration (Sanders, 1993), genetic (Lewis, Leach and Wood-Robinson, 2000, Pash1ey, 1994), ecology (Griffiths and Grant, 1985, Munson, 1994), classification (Trowbridge and Mintzes, 1988), the circulatory system (Yip, 1998), vertebrate and invertebrate (Braund, 1998) and energy (Boyes and Stanisstreet, 1991). From these studies revealed that students‟ misconception about different concepts of biology, students leave secondary school with a distorted view of concepts, objects and events. In the connection with cell structures and cell functions students‟ idea of these concepts and their conceptual difficulties or misconception will be investigated in different studies. Students are expected to know that all organisms including animals, plants, fungi and microorganisms are made up of cells, cells vary in size, shape and specialized functions, most cells are so small that their details can be seen only with a microscope, living things can be made of just one cell to many millions of cells, some organisms are made of many types of cells and many of each type, in single-celled organisms such as bacteria the single cell carries out all of the functions needed for the organism to stay alive, in organisms made of many cells individual cells work together with or depend on other cells to carry out their essential life functions, in multi cellular organisms the structures that make up those organisms including brain, muscles, skin and lungs in animals and stems and flowers in plants are made up of cells (Dreyfus and Jung wirth, 1988). Research has shown that students have difficulty making the connection between molecular and cellular organization (Driver, Rosalind, Squires, Ann, Rush worth, Peter, Wood-Robinson and Valerie, 1994). Students seem to understand that both atoms and cells are made up of smaller parts including the nucleus. However, they struggle to conceptualize the foundational principal that all matter including cells is made of atoms. This misunderstanding seems to perpetuate beyond differentiation between cells and atoms in their understanding of the structure and function of macromolecules. The learning goals set by the American Association for the Advancement of Science (AAAS) (1994) for the topic of cell structure and function for grades 9-12 include understanding that cell structure affects function and understanding that living cells are made of chemical elements. Additionally, the 9 Virginia Standards of Learning for Biology (VSLB) (2003) include understanding the structure and function of macromolecules and learning key differences between prokaryotic and eukaryotic cells. These standards help shape the curriculum for high school biology in Virginia and make up a continuous theme throughout the course. According to the American Association for the Advancement of Science (1994) students should experience a progression of their understanding of cell structure and function as they move through the grade levels. As elementary students they should have an understanding that some parts of organisms must be seen through a magnifying glass and then as they enter the upper elementary grades them should begin to form the concept of a cell as the basic unit of life. Finally, as they exit middle school students should have a clear understanding of basic cell function. By the end of the 12th grade students should have knowledge and understanding of the nature and function of proteins and the specialization of organelles within the cells including the cell membrane. Driver et al. (1994) a leader in misconception research has discovered that students often confuse the concepts of molecules and cells. Often times, students have a very general concept of molecules and cells both of which contain a nucleus and are surrounded by other small things. This confusion seems to stay with children though the teenage years. Also, students at the high school level tend to think that larger macromolecules such as proteins and carbohydrates are made of cells rather than atoms. They did not understand the difference between cells and molecules. More confusion has been found in students‟ ability to differentiate the sizes of cells and atoms. Many students at the high school level believe that cells and molecules of protein are the same size. Driver et al. (1994) research also found that students believe single-celled organisms contain intestines and lungs. A large number of prior studies reported that primary and Secondary School students have many conceptual problems concerning cell biology and genetics (Flores et al., 2003, Lewis and Wood-Robinson, 2000 and Marbach and Stavy, 2000). However, any detailed research related to biology students‟ misconception about cell biology and cell division was not found. If higher education curriculum designers knew students‟ misconception it might be helpful to prepare effective teaching strategies. Teachers can play an important role in teaching scientific concepts and from a constructivist perspective students should gain meaningful knowledge about biological concepts like cell biology and cell division. Biologically literate 10 students should be able to use and apply basic biological concepts when considering biological problems or issues. Prior studies have shown that students experience difficulties in learning concepts related to the cell division process (Kindfield, 1994). Cell division constitutes the basis for genetics, reproduction, growth, development and molecular biology subjects in the biology curriculum. As a matter of fact, a majority of the students evaluated topics such as gene, DNA, chromosome and cell division as difficult to learn topics (Oztas, Ozay and Oztas, 2003). Research on students‟ conceptual understandings often indicates that even after being taught students use misconception different from the scientific concepts (Lewis et al., 2000, Yesilyurt and Kara, 2007). Reasons for these misconception include students‟ inability to differentiate between doubling or replication, pairing or synapses and separating or disjunction, as well as determining whether or not these processes occur in mitosis, meiosis or both (Smith, 1991). Further misconception includes a lack of understanding of basic terms confusing chromatids with chromosomes or replicated chromosomes with un replicated chromosomes etc. (Kindfield, 1994). This is a concern for instructors because cell division processes are fundamental to the understanding of growth, development, reproduction and genetics (Chinnici et al., 2004, Cordero and Szweczak, 1994). Studies conducted on problemsolving related to genetics revealed that students have some misconception regarding the stages of meiosis (Brown, 1990, Stewart and Dale, 1989). Accurate organizing of many concepts in cell biology is dependent on the degree of understanding cell division (Smith and Kindfield, 1999). As a matter of fact, a study related to genetics mentioned that students possess misconception and inadequate knowledge about the behavior of chromosomes and transference of genetic material during cell division. It further suggested that such misconception lead to conceptual problems in genetics (Kibuka-Sebitosi, 2007). Yenilmez, A. and Tekkaya, (2006) studied the misconception possessed by 9th grade students relating to cell division and the effect of the conceptual teaching regarding elimination of such conceptions. They hypothesize that conceptual teaching is an effective method for understanding the concepts related to cell division and for elimination of misconception. (Lewis et al., 2000) studied the students‟ levels of understanding in regards to mitosis, meiosis and fertilization. 11 Students possess inadequate knowledge and numerous misconceptions related to the physical relationships between the genetic material and the chromosomes and the relationships between the behavior of the chromosomes and continuity of the genetic information. Lewis et al. (2000) further emphasized the fact that the students mainly experience difficulties for explaining the relationships between the cell, nucleus, chromosome and gene concepts and the similarities and differences between mitosis and meiosis. Clark and Mathis (2000) indicated that students experience difficulties particularly for discriminating chromatids, chromosomes and the homologous parts of the chromosomes during the cell division process, conclusions of the study have shown that these difficulties related to the structure and behavior of the chromosome can be easily identified and removed by means of models. Atilboz (2004) studied the level of understanding and misconception of 9th grade students related to mitosis and meiosis, from this study students experience difficulties in understanding fundamental concepts such as DNA, chromosome, chromatid, homologous chromosomes, haploid and diploid cells and the relationships between such concepts and possess some misconception. Saka, Cerrah, Akdeniz and Ayas, (2006) have shown that science student have misconception particularly regarding the concepts of gene and chromosome in accordance with their findings obtained from written responses and drawings. Kruger et al. (2006) studied the concepts of students regarding cell division and growth, the study revealed that students generally focus on the increase occurring with number of the cells, as a result of cell division and disregard the growth occurring in the cells. Kruger and colleagues also indicated that such difficulties experienced during understanding such concepts might be overcome by learning activities that researchers have developed. Riemeier and Gropengieber (2008) analyzed the difficulties in learning as experienced by the 9th grade students regarding cell division and their conceptual understandings with in teaching experiments. They have shown that well planned teaching activities for the cell biology and cell divisions might enhance the conceptual development process and might contribute to the conceptual learning by the students. It is obvious from the literature that misconception related to cell division processes lead to a series of problems for the biology teaching. When attending their biology classes students bring their perceptions, prejudices and former experiences in conflict with the scientific facts. This situation causes 12 various problems to arise during their biology classes. Keeping knowledge or conceptual frames of the students in line with the scientific facts can only be possible with effective conceptual teaching. 2.4. Methodologies for Investigating Students’ Misconceptions in Biology Science education researchers have widely surveyed students‟ knowledge in various domains known as students‟ misconception or alternative conceptions (Wandersee, Mintzes and Novak, 1994). Researchers have developed methods to explore student alternative conceptions for instance interviews (Bell, 1995, Posner and Gertzog, 1982) and concept maps (Novak and Gowin, 1984). However, these methods often require additional training and amounts of time to conduct, analyze and to make interpretation (Ruiz-Primo and Shavelson, 1996). There are a number of techniques used to determine conceptual understanding and misconception of students. Open-ended questions, two-tier diagnostic tests, interviews and drawings may be given as examples of these techniques. Using drawings to access student‟s thinking has been a feature of educational research. Students can present a broad spectrum of ideas through drawings (Rennie and Jarvis, 1995). Drawings have been used broadly in science education studies of students‟ conceptual understanding (Ben-Zvi Assaraf and Orion, 2005). It is recognized that drawings expose students‟ true understanding and conceptualization of basic scientific ideas and concepts. This is in contrast to what is exposed by standard written texts where students can repeat what they learned in class without revealing their misconception (Scherz and Oren, 2006). Student drawings in the area of biology can provide useful insight into common misconception or alternative conceptions (Bahar et al., 2008; Bowker, 2007; Kose, 200; Prokop and Faneovieova, 2006). As a technique for exploring ideas drawing taps holistic understanding and prevents students from feeling constrained by attempting to match their knowledge with that of the researcher (White and Gunstone, 2000). Thus, by using simple drawings biology educators can gather large amounts of data on the mental models students have about scientific concepts. Before misconception can be corrected they need to be identified. Since identification of misconception is needed to develop strategies to provide student with the accurate conceptual 13 knowledge. As mentioned earlier, misconception also developed by the student during the lesson if they are not detected and corrected immediately they will be adversely affecting the students' subsequent learning. This is a major source of learning problems in schools. In many countries, including Ethiopia assessment can be done at the end of a semester. However, this kind of assessment is not appropriate as a feedback on teaching. The teacher has no idea of how well or how poorly his students have learnt until at a very late stage. In order to identify and analyze misconception at an early stage, various forms of assessment should be used throughout a course. For example, quiz and discussion can take place any time during the lesson which provides opportunities for students to express their own ideas c1early. A short test given at the end of a topic also helps to motivate the students to review their work. A concept map constructed by each student is an excellent way of not only the reviewing a given topic but also detecting students' specific misconception. The nature and uses of interviews, multiple choice test and two-tier diagnostic instrument are discussed in the following sections. 2.4.1. Interviews Interviews can be structured, semi-structured or unstructured. In a structured interview a series of questions called a protocol is prepared prior to the interview and the interviewer has to follow rigidly the series of questions. In a semi-structured interview the interviewer also follows a sequence of questions prepared beforehand but he or she is allowed to probe the interviewee's answers with additional questions. In an unstructured interview the interviewer asks open-ended questions and based on the response given by the interviewee more specific follow-up questions are asked to probe any point of interest. Carr (1996) believed that unstructured interviews are difficult to sustain and are confrontational for interviewees so the interviewer must have a set of questions in mind for use when necessary. Interview methods, for example, interview-about-instances and interview-about-events (Carr, 1996) are very useful for exposing the nature of students' understanding and possible misconception. An interview about an instance is a deep probe of the student's understanding of a single concept (White and Gunstone, 1992). It is a conversation that an expert has with one student focused by initial questions about situations represented in a series of line 14 diagrams that checks not only whether the student can recognize the presence of the concept in specific instances but also whether the student can explain his or her decision. The quality of the student's understanding can be determined by his or her explanation. Interviews-aboutevents are similar probes though the emphasis is now on the student's interpretation of a natural phenomenon or social occurrence and his or her ability to explain it (White and Gunstone, 1992). Interviews also can involve the manipulation of concrete objects (Lazarowitz and Tamir, 1994) and students can be asked to explain the outcomes of their manipulations, for example, the results obtained when the seedling is put in the dark place. Interviews are highly flexible because they allow the interviewer to change his or her mode of questioning. When required, the interviewer can rephrase the questions if the interviewee does not understand the questions and he or she can probe any response to obtain clarification and elaboration from the interviewee. Thus, the interview allows the interviewer to probe the interviewee‟ ideas in as much detail as desired (Taber, 2000). The interview situation also allows the interviewee to ask questions, for example, to clarify perceived or actual ambiguities before attempting to answer a question (Osborne and Gilbert, 1980). An advantage that interviews have over written answers is that students cannot easily ignore a question and give no answer or omit to give a reason for an answer or simply produce an answer by guessing. 2.4.2. Multiple Choice Tests Multiple choice tests have been used for measuring students' understanding of concepts as they enable a large number of students to be sampled in a given amount of time as compared to time-consuming interviews. These tests are also easy to administer and score and the results obtained are also easily processed and analyzed (Taber, 2000). However, there are problems associated with the pencil-and-paper tests. For example, multiple choice tests make some demands on the reading comprehension skills of the respondents and students do not always perceive and interpret test statements in the way that test designers intend (Hodson, 1993). Since they have little option for clarification, misunderstandings do occur and this affects the validity and reliability of the tests. 15 Strategies such as time-management, error avoidance, checking responses and elimination of incorrect answers do not damage the validity and reliability of a test, while strategies that take advantage of consistent idiosyncrasies of the test constructor such as grammatical agreement, length of response, location of response and previous emphases of the test constructor. Guessing when students do not know the answer is also a problem in multiple choice tests. However, Tamir (1990) expressed his opinion that if a test consisted of cognitively high level items, students should be advised to attempt all items making educated guesses where necessary, for example, by narrowing down the possible choices through the elimination of incorrect responses. Tamir (1990) state that the development of multiple choice tests on student conceptions has the potential to make a valuable contribution to the body of work in the area of students‟ conceptions and to enable classroom teachers to more readily use the findings of research in their lessons. Ben-Zvi and Hofstein (1996) believed that research in student conceptions had only limited impact on teaching and learning in schools one of the reasons being teachers‟ unawareness of the learning difficulties and misconception that exist among their students. Thus, teachers could use such tests as a tool to diagnose student conceptions and steps could then be taken to help students see that the science concepts make more sense than their conceptions hence increasing the status of the science concepts (Hewson, 1996). Classroom discussion of the items in such diagnostic tests provides a means of challenging misconception as students are often well-motivated to know the right answers after they have completed such an activity. Tamir (1990) pioneered the use of tests derived from a specified and limited content area as well as the use of distracters which were based on students' answers to essay questions and other open-ended questions in the multiple choice items. He believes that normal multiple choice items tend to overestimate students‟ knowledge as students may not be able to explain adequately their choices. He also suggests that students should be made to justify their choices in the multiple choice items so that more information can be obtained on the students‟ knowledge. Incorrect justifications could also provide a rich source of students‟ misconception. 16 2.4.3. TTDT Two-tier test is a pencil and paper test in a multiple choice format that proposed by science educators to diagnostic students‟ misconception (Odom and Barrow, 1995). The two tier test allows teachers not only understand students‟ scientifically incorrect ideas but also explore students‟ reasoning behind these ideas. Moreover, it is easy for teachers to assess misconception of a larger sample of students in a more efficient and relatively straightforward method. It is recently widely used in science education research (Voska and Heikkinen, 2000). Duit (1995) described that how two-tier diagnostic tests can identify and be used to evaluate student conceptions in specific content areas. The first-tier choices examine factual knowledge while the second-tier choices examine the reasons behind the first tier. To ensure the validity of the diagnostic instrument, the propositional knowledge statement is to be specified clearly. The items in the test are to be developed based on known student conceptions responses from students to interviews and free response items. This methodology has been used to develop two-tier diagnostic tests in chemistry these tests were developed for covalent bonding (Peterson and Treagust, 1989) and chemical equilibrium (Tyson and Bucat, 1999) and in biology on diffusion and osmosis (Odom and Barrow, 1995). Two-tiered questions have two main benefits over conventional one-tiered questions. The first is a decrease in the measurement error. In a one tier multiple choice questions with 5 possible choices there is a 20% chance of correctly guessing the answer. These random correct guesses must be accounted for in the measurement error. A two-tiered question is considered correct only if both tiers are answered correctly. As a result, a student responding to a question with 5 choices in the first tier and 5 in the second has only 4% chance of randomly correct guessing. The second benefit to the two-tiered format is that it allows for the probing of two aspects of the same phenomenon. In the first-tier, students are asked to predict the outcome of a content knowledge and the second-tier asks for an explanation. This allows the probing of the phenomenological domain with the first-tier and the conceptual domain with the second (Treagust, 1988). The rules of development of two-tiers multiple choice diagnostic tests used in this study were described by Treagust (cited in Wang, 2004). In this test, the first-tier of 17 each item consists of a content question of five choices the second part of each item contain a set of five justifications for the answers to the first part. Included in these justifications are the correct answer and two to five distracters. Distracters are derived from students‟ misconception gathered from the literature, interviews and free responses. In advocating different assessment procedures to probe students‟ understanding of scientific concepts (Schmidt, 1991) recommended that information relating to erroneous concept held to be true by students should be included in the tests that have distracters. This line of research in assessment has included the development of multiple choice tests items that have distracters based on students‟ conceptions. 2.5. Methods of Removing Students’ Misconceptions To promote meaningful learning, ways must be found to eliminate or remove misconception. Various instructional methods can be used for this purpose. One such method involves the use of a conceptual change approach. A conceptual change approach proposes that if students are to change their ideas, they must become dissatisfied with their existing conditions or dissatisfaction, new concepts must intelligible, plausible and fruitful (Posner et al., 1982). Several research studies suggested that instructional strategies leading to conceptual change such as concept maps, conceptual change texts, analogies and reputational texts could be employed to remove students' misconception and improving learning. Concept maps, conceptual change texts, conceptual change model and classical conceptual change are briefly discussed below. Concept Maps: Compartmentalization of concepts is a common problem in biology learning which occurs when concepts are studied with little integration. Students may be able to state correctly the individual events but often do not understand the relationship between them. An effective way to tackle this problem is to use a concept map. They are diagrammatic representations which show meaningful relationships between concepts in the form of proposition. Propositions are two or more concept labels linked by words which provide information on relationships or describing connections between concepts. Concept maps serve to clarify links between new and old knowledge and force learners to externalize those links. From these aspects, concept mapping has become increasingly useful as an instructional 18 strategy for the diagnosis of students' misconception by facilitating meaningful learning (Guastello, 2000; Kinchin, 2000; Novak, 1990; Okebukola, 1990; Sungur et al., 2001 and Yılmaz, 1998). Conceptual Change Text: Conceptual change text is an instructional technique that creates conceptual change on students' minds while promoting meaning learning. Conceptual change texts are designed to make students aware of both their misconception and scientifically accepted concepts. Misconception is directly stated within the text and helped students to understand and apply the target scientific knowledge through the use of more plausible and intelligible explanations (Erdmann, 2001; Ozkan, 2001; Sungur et al., 2001 and Yılmaz, 1998). Thus, conceptual change instructional techniques have to use to change students' misconception with the scientific view of world and taught the concepts in a meaningful manner to students. Misconceptions also arise when the learning fails to induce the conceptual change in students' minds. These strategies not only help teachers analyze the ideas of their students but also help students get a better understanding of biological concept. Conceptual Change Model: Students‟ conceptual ideas are based on personal experiences and require real changes in thinking and adjustments at the neural levels (Zirbel „‟ learning and concept formation”). Unfortunately, students often are not open to new ideas, in which case a radical approach is needed to change preexisting concepts. With this mind, posner et. al., (1982) proposed the conceptual change theory, a combination of two theories: one from the history and sociology of science (Kuhn, 1970), and one from developmental psychology (Piaget, 1977). Posner et.al (1982) hypothesized that there are four essential conditions for conceptual change: Dissatisfaction with one‟s current conception, followed by degree to which the new conception is deemed b) intelligible c) plausible and d) fruitful. The interpretation of student responses as driven by alternative conceptions suggests that learning may involve changing a person‟s conceptions in addition to adding new knowledge to what is already there. This view was developed into a model of learning as conceptual change model (CCM) by Posner et al., (1982) and expanded by Hewson (1981, 1982). From this point of view, learning involves an interaction between new and existing conceptions with the outcome being dependent on the nature of the interaction. 19 A central prediction of the conceptual change model is that conceptual changes do not occur without concomitant changes in the relative status of changing conceptions. Learning a new conception means that its status rises, i.e., the learner understands it, accepts it, and sees that it is useful. If the new conception conflicts with an existing conception, i.e., one that already have high status for the learner, it cannot be accepted until the status of the existing conception is lowered. This only happens, according to the conceptual change model, if the learner holding the conception has reason to be dissatisfied with it. Classical Conceptual Change: Further development of the classical conceptual change ideas: classical conceptual change is considered not as a replacement of an incorrect naïve theory with a correct theory but rather, as an opening up of conceptual space through increased metaconceptual awareness and epistemological sophistication, creating the possibility of entertaining different perspectives and different point of views” (Vosniadou, 2008). Theoretical developments in the area of conceptual change that means students‟ conceptions towards multiple conceptual changes, conceptions on the nature of science, meta-cognitive conceptions science processes, tentativeness limitation multiple theories, views of teaching and learning, methods/means of scientific inquiry and epistemological views of teaching and learning. Teachers‟ conceptions have proven limited. Conceptions on the content level conceptions on the Nature of Science and Science Processes - views of teaching and learning science meta-cognitive conceptions teachers‟ conceptions have to undergo conceptual changes. Basically the same conceptual change frameworks for addressing students‟ conceptions have proven valuable to develop teacher conceptual change approach. 20 3. RESEARCH METHODOLOGY 3.1. Description of the Study Area Kelafo is one of the woredas in the Somali Region of Ethiopia. Part of the Gode Zone, Kelafo is bordered on the south by the Somalia, on the west by Adadle, on the northwest by Gode, on the northeast by the Korahe Zone and on the east by Mustahil. The Shebelle River is flowing through this woreda. The major town in Kelafo woreda is Kelafo. The average elevation in this woreda is 374 meters above sea level. As of 2008, Kelafo has 35 kilometers of all weather gravel road and 300 kilometers of community roads and about 6.36% of the total population has access to drinking water. This woreda has a total population of 77,471 people of whom 41,583 are males and 35,888 are females. 11,346 (14.65%) people are urban inhabitants and a further 5,397 (6.97%) are pastoralists. 98.09% of the population is Muslim. This woreda is inhabited by the following Somali groups, the Bah Geri of the Ogaden, Hawadle and Rer Bare. The largest ethnic group reported in Kelafo is Somali 82,353 (99.6%) (CSA, 2007). 3.2. Research Design To assess grade 10 and 11 students‟ misconception about cell biology and cell division at KSPS, mixed probe design was employed with a cross-sectional descriptive survey method. 3.3. Study Population, Samples and Sampling Procedures The KSPS was selected purposively since it is the only high school found in the study woreda. Due to limitation of resources, only two grades (grade 10 and 11) were selected purposively for this study. All the grade 10 and 11 students who were enrolled during the 2013/2014 academic year were considered as target population for the present study. All students in the selected study grades (grade 10 and 11) were participated in the present study. Different numbers of male and female students from grade 10 and 11 were participated for interview, TTDT and questionnaire. Accordingly, a total of 165 students (81 and 84 students from grade 10 and 11, respectively), were involved in this study. From the total of 165 students 8, 37 and 120 students were participated in interviews, open-ended questionnaires and in TTDT, respectively (Table 1). The study participants were drawn using stratified 21 systematic random sampling methods. In addition, three biology teachers of grade 10 and 11 at KSPS were involved in this study. Table 1: Students‟ sample size Grades and sample size Grade 10 Data collection tools M F Interview 3 1 Open-ended questionnaires 11 TTDT Total Grade 11 T Total M F T M F T 4 2 2 4 5 3 8 7 18 10 9 19 21 16 37 34 25 59 35 26 61 69 51 120 48 33 81 47 37 84 95 70 165 M-Male, F-Female and T-Total 3.4. Data Collecting Tools In this study different data collecting tools were employed for different purposes. These include document analysis of the grade 10 and 11 biology text books and syllabi were made to identify key concepts and propositional knowledge statements related to cell biology and cell division. Questionnaire survey, interview and classroom observation check list were used in this study. Their details are described below. 3.4.1. Document Analysis This was intended to identify the content boundaries of cell biology and cell division. Grade 10 and 11 biology textbook, teachers‟ guide and syllabi were used to assess and determine the scope and specify the subject contents related to the study topic that would directly linked to the actual curricular and instructional resources being used. The researcher identified and set outline, particularly the key concepts and propositional knowledge statements related to cell biology and cell division topics. These are later verified and validated by the biology teachers of grade 10 and 11 at KSPS. 22 3.4.2. Interview guide Sixteen semi-structured interview questions were prepared based on target concepts and propositional knowledge statements that were identified from grade 10 and grade 11 biology textbooks, teacher‟s guide and biology syllabi related to the study topics. These questions were first reviewed by three KSPS biology teachers for its validity. Eight sampled students were interviewed individually turn by turn. The interview took place in the students‟ classroom where there was silence and bright light. Each interview with selected students lasted for 25 to 30 minutes. When students got the questions very difficult the researcher provided additional information but when students provided a wrong answer the researcher did not correct them. Besides, when the student‟s response was unclear, follow up questions were used to elicit additional responses. The responses obtained from the interview were categorized into correct answered (CA), partially correct answered (PA), wrong answered (WA) and misconception (M) in such a way that they were used for developing open-ended questionnaire and two-tier diagnostic multiple choice test item (Appendix II). 3.4.3. Questionnaires Fifteen open-ended questionnaires were prepared according to the observed students‟ response during the interview and according to the related literature (Appendix III). For its validity and reliability the pilot test was given at Gode Secondary and Preparatory School. Most of the questionnaires items were adapted from interview. In addition, close-ended questionnaires were prepared and administered to three biology teachers at KSPS (Appendix IV). The open-ended questions were administered for 37 students in their classrooms where there was suitable situation that means bright light and no noise disturbance. All the questionnaires were completely filled by the students and returned. Volunteer teachers assisted the researcher during the administration of the questionnaire. The time allowed to fill the questionnaires was 60 minutes. The responses obtained from open-ended questionnaires were grouped under correct response, wrong response, no response, meaningless response and misconception in such a way that they were used for preparing TTDT item of cell biology and cell division. 23 3.4.4. TTDT of Cell Biology and Cell Division TTDT for cell biology and cell division was developed by the researcher based on previously identified target concepts and propositional knowledge statements and from students‟ responses in the interview and open-ended questionnaires. For its validity and reliability the pilot test was given at Gode Secondary and Preparatory School. The test was prepared based on the procedure described by Treagust, (1988) (cited in Wang, 2004) that involved three parts. These were: first, define the content domain under the topics of cell biology and cell division in terms of the target concepts and propositional knowledge statements (Appendix VII), second, obtaining information about students‟ prior conceptions through interview and open-ended questionnaires and third, prepare the two-tier diagnostic test based on target concepts and propositional knowledge statements and students‟ prior conceptions that was documented in part I, part II and part III, respectively (Appendix I). The TTDT was a multiple choice type of test that consists of two-tiers or parts. The first-tier of each multiple choice item consisted; of content knowledge related question designed to assess the students‟ knowledge level about cell biology and cell division and has two to three choices. The second-tier of each multiple choice item contained the reasons for selecting the responses to the first-tier and a set of four choices that could be possible reasons for the answers given to the first part. The reasons consist of the designated correct answers together with the distracters that were identified by the interview and open-ended questionnaires. The target concepts and the propositional knowledge statements influenced the first-tier, whereas the students‟ interview and open-ended questionnaires responses influenced the distracters of second-tier of the item. Biology teachers and instructor of measurement and evaluation were involved in validating all the items and confirmed that this was appropriate for grade 10 and grade 11 students in order to determine their understanding. Finally, the revised test consisted of 12 items (Appendix V). 3.4.5. Classroom Observations Classroom observation was conducted with classroom observation check list to evaluate the effectiveness of instructional methods used by biology teachers to remediate students‟ misconception on cell biology and cell division. Observation of biology classroom was 24 carried out by using structured observation checklist that was emphasized mainly on the teaching methodology (Appendix VI). To cover the topics of cell biology a total of 29 periods were needed for grade 11and under the topics of heredity, there were sub topics mitosis and meiosis, chromosomes and genes 6 periods needed for grade 10. The duration of each period was 40 minutes. 14 classroom observations were conducted at grade 11 and 6 classroom observations at grade 10. Therefore, 20 classroom observations were conducted the total 35 periods of both grades. The observations were conducted on different sub topics under the main topics of cell biology for grade 11 and all sub topics including cell division under the main topics of heredity. The classroom observations took four weeks for grades 11 and two weeks for grade 10, it was conducted in 2013 /2014 academic year. 3.4.6. Procedures of Data Collection First define the content domains under the topics of cell biology and cell division. This is intended to define the content boundaries for the students understanding of cell biology and cell division. Then obtaining information of students‟ prior conceptions about cell biology and cell division has been done through interview and open-ended questioners. Next Preparation of cell biology and cell division TTDT, Finally Classroom observation was conducted to evaluate the effectiveness of instructional methods used by biology teachers to remediate students‟ misconception on cell biology and cell division. 3.5. Methods of Data Analysis The research strategies employed in this study were used both qualitative and quantitative methods. The quantitative methods were used to examine the data of TTDT, cronbach alpha reliability coefficient, discrimination and difficulty indices, percentage, frequency and mean. The analysis and interpretation of qualitative methods has been done using conceptualization, explanations and argumentation. 25 4. RESULTS AND DISCUSSIONS 4.1. Identified Key Concepts and Propositional Knowledge Statements about Cell Biology and Cell Division List of key concepts and their corresponding propositional knowledge statements related to cell biology and cell division in grade 10 and 11 biology text books and syllabi are summarized and presented in table 2 and 3, respectively. Table 2: Summary of key concepts and their propositional knowledge statements that are included in grade 10 biology textbook and syllabus related to understand cell division. No Key concepts 1 Types of cell divisions: - Cell division is the process where a single living cell splits Mitosis and Meiosis. Propositional knowledge statements to become two or more distinct new cells. -The two forms of cell division mitosis and meiosis are the biological mechanism by which the principles of heredity and evolutionary theory are realized. -Mitosis is simple cell division that creates two daughter cells that are genetically identical to the original parent cell. -Meiosis is the production of daughter cells having half the amount of genetic material as the original parent cell. Such daughter cells are said to be haploid. 2 Chromosome and genes -Chromosomes are organized structures of DNA and proteins that are found in cells. -A chromosome is a singular piece of DNA which contains many genes regulatory elements and other nucleotide sequences. -A gene is the basic functional unit of heredity. It made up of DNA act as instructions to make proteins. -Genes carry the information that determines your traits which are features or characteristics that are passed on to you or inherited from your parents. 26 Table 3: Summary of key or target concepts and their propositional knowledge statements that are included in grade 11 biology textbook and syllabus to understand cell biology. No Key concepts Propositional knowledge statements 1 Cell theory -All living organisms are composed of one or more cells, the cell is the most basic unit of life and all cells arise from pre-existing living cells. -All organisms including animals, plants, fungi and microorganisms are made up of cells. -Most cells are so small that their details can be seen only with a microscope. 2 Cell structures and its -There are many different types of cells in terms of size, functions. structure and function. -Cells vary in size, shape and specialized functions. -All cells are composed of complex molecules made by the cells themselves from simpler molecules such as amino acids, simple sugars and fatty acids that enter the cells from outside the cells. -In multi cellular organisms, cells provide structural support for the organism they are part of and carry out essential life functions for that organism. 3 Types of cells -Different body structures are made up of different types of cells. -The different body structures of plants and animals including brain, muscles, skin and lungs in animals and stems and flowers in plants are made up of different types of cells. -There are many different types of cells in terms of size, structure and function. All cells have certain characteristics in common. -The different types of cells that make up the body parts of animals develop from one single cell. 27 In grade 10 biology text book and syllabus, there was the concepts of cell division but there was no the concepts of cell biology. However, grade 10 students learned it in more detail the concepts of cell biology in grade 9. Similarly, in grade 11 biology text book and syllabus there was the concepts of cell biology but there was no the concepts of cell division. However, they were already learned the concepts of cell division in grade 10. So the concepts of cell biology and cell division were described in different grade level of biology text books and syllabi. The results showed in tables 2 and 3 are summary of key concepts and their corresponding propositional knowledge statements related to topics of cell division in grade 10 and to cell biology in grade 11 biology text books and syllabi. The content framework of the topics of cell biology and cell division was described through the review of grade 10 and 11 biology textbooks, teacher‟s guide and syllabi and prepared the target concepts and propositional knowledge statements. The researcher has identified two key concepts and 22 prepositional knowledge statements related to cell division, and three key concepts and 24 prepositional knowledge statements related to cell biology of grade 10 and 11 biology, respectively. The results indicated that grades 10 and 11 biology text books and syllabi related to cell biology and cell division were complete and sufficient to understand the topics. However, the lists of target concepts and propositional knowledge statements, they met the requirements of grade 10 and grade 11 biology books and syllabi on topics of cell biology and cell division. Moreover, these results were used to prepare the two-tier diagnostic test of cell biology and cell division. The teachers should make the content analysis for the topics that contain the concepts difficult for understanding of the students. This process was better if it started by identifying the main or target concepts in the topic followed by breaking down each concept to see how it was explained in terms of other more fundamental concepts and then relates the links between the different concepts. Taber (2000) suggested that a teacher should undertake a content analysis when preparing to teach complex topics in order to determine the relationship between the relevant concepts and logical order in which the concepts should be presented. The complete lists of propositional knowledge statements of grade 10 about cell division and grade 11 about 28 cell biology which were found in biology text books and syllabi are summarized and presented in more details (Appendix VII). 4.2. Assessment of Students’ Misconception about Cell Biology and Cell Division In order to determine whether the grade 10 and 11 students had prior knowledge and or misconception about cell biology and cell division a TTDT was conducted and the results are summarized and presented in table 4. Table 4: Summary of grade 10 and 11 students‟ misconception about cell biology and cell division of TTDT Variables Grade 10 (N=59) Grade 11 (N=61) Both grade (N=120) No. of items 12 12 12 Cronbach Alpha 0.86 0.8 0.83 Mean 7.1 6.3 6.7 Discrimination Indices Mean 0.42 0.4 0.41 Difficulty Indices Mean 0.36 0.38 0.37 Note: N-Number of students The result in table 4 shows that the same 12 TTDT items were prepared for both grades. The TTDT needed to consider both item discrimination and difficulty, whether the item allows the knowledgeable students to perform better than the less knowledgeable students. The discrimination indices for the items in the cell biology and cell division diagnostic test an average value of 0.41 for both grades. The entire test items prepared to identify students‟ misconception about cell biology and cell division was presented (Appendix V). Lien (1971) suggested that the discrimination indices of the item greater than 0.3 is acceptable without further revision of the test items. The TTDT item reliability coefficients, Cronbach alphas were calculated to be 0.86 for grade 10 and 0.8 for grade 11 students. This shows that almost both grades have similar reliability coefficients. Moreover, this test was moderate with mean value 6.7 for both grades. The difficulty indices of cell biology and cell division diagnostic test an average value of 0.37 for both grades (Table 4). This shows that the two-tier diagnostic test of cell biology and cell 29 division was difficult for secondary school students. However, it was effective to identify students‟ misconception and their level of conceptual understanding on the selected topics of the study. For assessing understanding, items with difficulty indices of 0.9 is considered as easy type, items with difficulty indices of 0.5 is consider as average type and items with difficulty indices of 0.1 is consider as difficult type (Anastasi, 1982). In this study, students‟ misconception about cell biology and cell division detected by interview, questionnaires and two-tier diagnostic test. Their details are described below. 4.2.1. Students’ Misconception Identified by Interview Results of frequency of the response categories of interviewees and respondents for interview about students‟ prior knowledge of cell biology and cell division are summarized and presented in table 5. To find out students understanding related to the topics of cell biology and cell division, their prior conceptions were assessed through interview. Students‟ responded about their prior conceptions of cell biology and cell division were categorized into correctly answered, partially answered, wrongly answered and misconception. The complete responses of the students‟ prior conceptions are summarized and presented in Appendix VIII. 30 Table 5: Frequency of students‟ response categories for interview questions about their prior conceptions of cell biology and cell division Students‟ responses (N-8) Items CA f (%) PA f (%) WA f (%) M f (%) 1 1(12.5) 1(12.5) ___ 6(75) 2 5(62.5) 2(25) 1(12.5) ___ 3 1(12.5) 1(12.5) 1(12.5) 5(62.5) 4 ___ 2(25) 2(25) 4(50) 5 6(75) 2(25) 1(12.5) ___ 6 2(25) ___ 1(12.5) 5(62.5) 7 1(12.5) 2(25) 1(12.5) 5(62.5) 8 5(62.5) ___ 3(37.5) ___ 9 6(75) 2(25) ___ ___ 10 5(62.5) 1(12.5) 2(25) ___ 11 4(50) 2(25) 2(25) ___ 12 1(12.5) 1(12.5) 1(12.5) 5(67.5) 13 1(12.5) 2(25) 1(12.5) 4(50) 14 1(12.5) 1(12.5) 2(25) 4(50) 15 1(12.5) 1(12.5) 1(12.5) 5(62.5) 16 ___ 1(12.5) 1(12.5) 6(75) (CA)-correctly answered, (PA) -partially answered, (W)-wrongly answered, (M)- Misconception and (-) no one answered. Based on the results shown in table 5, in items 1, 3, 4, 6, 7, 12, 13, 14, 15 and 16, more than half or majority of the interviewees had misconception about cell biology and cell division. However, misconception was not observed for question items 2, 5, 8, 9, 10 and 11. But a small number of the interviewees responded correctly for the above question items (table 5). Thus, these items were excluded from developing questionnaires and TTDT items of cell biology and cell division. 31 4.2.2. Students’ Misconception Identified by Questionnaires Results of frequency of the response categories of open-ended questionnaires about students‟ prior knowledge of cell biology and cell division are summarized and presented in table 6. The complete responses of the students‟ prior conceptions about cell biology and cell division were summarized in Appendix IX. Table 6: Frequency of students‟ response categories for open-ended questionnaires regarding their prior conceptions of cell biology and cell division Students‟ responses (N-37) Items CA 1 f (%) PA f (%) WA f (%) M f (%) NA (f %) 6(16.2) 5(13.6) 4(10.8) 20(54) 2(5.4) 2 4(10.8) 6(16.2) 7(18.9) 19(51.4) 1(2.7) 3 8(21.6) 5(13.6) 7(18.9) 11(29.7) 6(16.2) 4 12(32.4) 4(10.8) 5(13.6) 9(24.3) 7(18.9) 5 5(13.6) 9(24.3) 12(32.4) 7(18.9) 4(10.8) 6 10(27) 8(21.6) 10(27) ___ 9(24.4) 7 4(10.8) 3(8.1) 9(24.3) 21(56.8) ___ 8 8(21.6) 6(16.2) 11(29.7) 12(32.5) ___ 9 12(32.5) 11(29.7) 6(16.2) ___ 11(29.7) 10 3(8) 2(5.4) 5(13.6) 25(67.6) 2(5.4) 11 9(24.4) 10(27) 8(21.6) 10(27) __ 12 11(29.7) 7(18.9) 6(16.2) 8(21.6) 5(13.6) 13 9(24.3) 7(18.9) 5(13.6) 12(32.4) 4(10.8) 14 9(24.4) 5(13.6) 12(32.3) 11(29.7) ___ 15 15(40.5) 5(13.6) 7(18.9) ___ 10(27) CA-correctly answered, PA-partially answered, WA- Wrong answered, M-Misconception, NA-No answered and (-) no one answered. As it is shown in table 6, low percentage of the students correctly answered the items which probably indicate that students had content knowledge difficulties besides to the understanding of that knowledge or conceptual understanding. However, the more percentages of the students answered under the category of misconception. This shows many 32 students had misconception on those items. In items 1, 2, 7 and 10 above 50% of the students answered under the category of misconception, on these items students had conceptual difficulties on the concepts of the definition of cells, the difference between cells and atoms, importance of surface area to volume ratio in cells and purpose of cell division. Almost in all items, students‟ answers categorized under misconception were carefully read, rearranged and documented. These were used as distracters of the second tier or the reason options together with the students answer for interview questions (Table 5) during the preparation of two-tier diagnostic test of cell biology and cell division. 4.2.3. Students’ Misconception Identified by TTDT Items To find out students‟ misconception related to the topics of cell biology and cell division, their prior conceptions were collected through two-tier diagnostic test. Students‟ prior conceptions about cell biology and cell division were collected through the TTDT was categorized into four understanding categories those were understanding, partially understanding, misconception and not understanding (Table 7) and which were analyzed the results and presented below.( Appendix V) 33 Table 7: Frequency of students‟ response categories for TTDT items regarding their understanding of cell biology and cell division Grades Grade 10 (N-59) Grade 11 (N-61) N(T-T) N(T-F) N(F-T) N(F-F) N (T-T) N(T-F) N(F-T) N(F-F) Item f(%) f (%) f (%) f (%) f (%) f (%) f (%) f (%) 1 10(16.9) 43(72.8) 2(3.5) 4(6.8) 6(9.8) 41(67.2) 6(9.8) 8(13.2) 2 5(8.5) 42(71.2) 4(6.8) 8(13.6) 10(16.4) 36(59) 5(8.2) 10(16.4) 3 7(11.9) 40(67.8) 8(13.6) 4(6.7) 8(13.2) 38(62.8) 10(16.4) 5(8.2) 4 11(18.7) 28(47.5) 10(16.9) 10(16.9) 15(24.6) 25(41) 11(18) 10(16.4) 5 12(20.3) 27(45.7) 11(18.7) 9(15.3) 12(19.6) 20(32.8) 15(24.6) 14(23) 6 11(18.7) 29(49.1) 9(15.3) 10(16.9) 14(23) 27(44.3) 12(19.6) 8(13.1) 7 6(10.1) 38(64.4) 9(15.3) 6(10.2) 6(9.8) 39(63.9) 9(14.8) 7(11.5) 8 9(15.3) 45(76.2) __ 5(8.5) 7(11.5) 40(65.6) 8(13.8) 6(9.8) 9 7(11.9) 37(62.7) 7(11.9) 8(13.5) 14(23) 36(59) 6(9.8) 5(8.2) 10 __ 43(72.8) 9(15.3) 7(11.9) 8(13.1) 37(60.6) 9(14.8) 7(11.5) 11 20(33.9) 25(42.5) 10(16.9) 4(6.7) 12(19.6) 23(37.7) 18(29.5) 8(13.2) 12 12(20.3) 24(40.7) 13(22.1) 10(16.9) 9(14.8) 24(39.3) 11(18) 17(27.9) N (T-T) - Understanding, N (F-T) - Partial understanding, N (T-F) - Misconception and N (F-F) - Not understanding Items 1 and 9 referred to the definition and explanation of cell biology and cell division concepts. In item 1, 72.8% of grade 10 students and 67.2 % of grade 11 students had misconception. They understood cells are the building blocks of body and cell division is the process of cells separation into many cells (Table 7). The reasons of students‟ misconception were suspected to be due to concepts of daily language having different meanings in scientific language, vocabulary and unfamiliarity with cell structures and functions. whereas many curricula introduce them as the building blocks of all life, it has been reported that a common misconception children have is that of cells as being inside the body but not as making up the body that the term „building block‟ would imply (Dreyfus and Jungwirth, 1988). Even though, students had been learning about cell biology starting from Elementary school, they did not 34 clearly understand the concept of it. Thus, they thought that cell is simply a structural and functional unit of life. In item 9, another misconception held by students was the meaning of cell division. They thought that cell division is the process of cells separation into many cells. 62.7% of grade 10 students and 59% of grade 11 students had this misconception but cell division is division of a cell into two daughter cells with the same genetic material. Most likely the reason for their misconception may be the difference between the scientific and daily language and teachers‟ English language skills. About 72.2% of grade 10 students and 59% of grade 11 students thought that both atoms and cells are made up of smaller parts including the nucleus (Item 2). This belief of the students may be tied with their chemistry knowledge. Research had shown that students have difficulty making the connection between molecular and cellular organization (Driver et al., 1994). Students seem to understand that both atoms and cells were made up of smaller parts including the nucleus. However, they struggle to conceptualize the foundational principal that all matter including cells is made of atoms. This misunderstanding seems to perpetuate beyond differentiation between cells and atoms and into their understanding of the structure and function of macromolecules. The reasons for misconception may be faulty or insufficient perception of the concepts learnt. In item 4, the students were required to explain the role of nucleus in cells. 47.5% of grade 10 students and 41% of grade 11 students believed that nucleus center of holds all the supplies needed to make in the body and further they believed that cells holding all materials inside the nucleus. This misconception may be arisen due to students observed the nucleus always found at center of cells. However, the nucleus in a cell is the organelle in which the DNA and most genetic material are stored including many proteins. The main function of the nucleus is to regulate all cell activity. The nucleus also contains the hereditary information and has the remarkable ability of making the exact copies of it. The nucleus also regulates the synthesis of proteins and ribosome in the cytoplasm. Item 6, requested student to explain which structure of plants that photosynthesis is taking place. Accordingly, 49.1% of grade 10 students and 23 % of grade 11 students reasoned 35 correctly and suggested the correct reason as photosynthesis process is taking place in the chloroplast that consists of grana and stroma. However, 15.3% of grade 10 students and 44.3% of grade 11 students thought that photosynthesis is taking place in the mitochondria. This misconception of the students may be due to their knowledge that mitochondrion is the power house of all cells where many biochemical reactions take place to release energy. Many students of both grades had misconception on the concepts of surface area to volume ratio is important in cells? items 7, 64.4% of grade 10 students and 63.9% of grade 11 students. Students believed that very large cell has a larger surface area to volume ratio than a very small cell. But most of the students‟ misconception very large cell has a large surface area to volume ratio than a very small cell. This misconception may be arisen due students‟ confusions that they believe as the size of cell increased with surface area and volume would be increased. Surface area and volume are important the efficiently the cell is in obtaining oxygen it needs for respiration and in determining how the given material will interact with the world around it. As the size of cell increased surface area and volume were increased but surface area to volume ratio decreased. Consider a mouse and an elephant. If both were left in cold overnight the mouse would be in more danger of freezing because it has the large surface area to volume ratio. So it can lose more heat. The elephant would actually be able to use its large size to its advantage here and retain the heat in the large volume of its body. The mouse has a much larger surface area and volume ratio so all physiological adaptations to environments to the side of the mouse would be in danger of freezing to death much quicker than the elephant should temperatures fall. The common misconception indicated in item 8, was that most of the animal cells get energy for its function from the chemical bond energy in food molecules. More than half of the students from each grades, 76.2% of grade 10 students and 65.6% of grade 11 students thought that animal cells get energy for its function by synthesis of their own food. This misconception of the students, believed that animal cell makes their own food due to the process digestions. But animal cells get there energy from glucose which is made by the plant and ingested by the animal. The animal cells then take in the glucose and through cellular respiration convert it into ATP using their mitochondria which the cell uses as energy. Actually chloroplasts in a plant cell capture energy to produce glucose. In order to use that 36 energy all living things must go through the process of cellular respiration. Plants make their own source of glucose. Animals must ingest and digest food to obtain our glucose or by eating plants directly or eating animals that eat plants after we get the glucose into the cells then we go through the process of cellular respiration. In item 3, it was identified that 67.8% of grade 10 students and 62.8% of grade 11 students‟ responded that whether a cell is prokaryotic or eukaryotic, had misconception because they believed that the difference between eukaryotic and prokaryotic cells are the presence or absence of ribosome‟s (Table 7). This indicates that the students had conceptual difficulty about the prokaryotic and eukaryotic cells. The reasons for students‟ misconception may be insufficiency in the construction of relationships between the concepts and concepts, and teachers‟ English language skills. So both prokaryotic and eukaryotic cells separation whether or not the cell is partitioned by internal membranes or nuclear membranes. In item 5, the students of the two grades indicated that they had misconception about the difference between animal cells and plant cells. About 45.7% of grade 10 students and 32.8% of grade 11 students believed that animal cells carry out that cell wall and chloroplasts just like plant cells. Students believed that all cells contain the same organelles and the only difference was in their size. But the major difference in both of these cells apart from cellular differentiation is that plant cells contain chloroplast which helps to produce their food. Animal cells do not have chloroplast and they are dependent on plants that animals for their energy requirements. This misconception may arise due to the problem observed in textbook quality which lacks proper explanation of the subject matter and scientific facts related to animal cells and plant cells. In item 10, the students were required to compare about mitosis and meiosis in cells. In this item, the misconception identified was that mitosis and meiosis are functioning in an opposite and contrasting manner. This misconception probably arose from their biology textbook, instructional methods, unfamiliarity with cell structures, teacher confusion, not using appropriate teaching approaches while teaching topics and concepts and poor understanding of mitosis verses meiosis. This makes the students to have misconception on the concept how mitosis and meiosis occurs. This misconception was held by 72.8% of grade 10 students and 37 60.6% of grade 11 students. Responses of many students showed that as if there was a determined belief that mitosis and meiosis were mutually exclusive processes that occur at the same time in cells. In general this finding provides useful indicators that students had conceptual difficulties about the relationship between mitosis and meiosis in cells. On the other hand many of the students of each grade had great misconception about the type‟s cell biology and cell division in items 3, 5 and 10, respectively. In item 11, it was identified that 42.5 % of grade 10 students and 37.7% of grade 11 students had misconception as they responded that which phase of mitosis does chromatin change to chromosomes. This indicates that the students had conceptual difficulty that both chromosomes and chromatin are the same. Students may think that the two chromatids making up a single replicated chromosome are joined at fertilization and that they represent maternal and caring genetic information. This misconception arose may be the students difficult to differentiate the word chromosomes and chromatin. Barras (1984) suggested that sometimes textbook authors use misleading words that lead students to have misconception. Hence, textbooks should not be regarded as a document which was free of error and a document that explain and illustrate concepts perfectly. In items 12, the students were required to explain which phase were the longest phases of the cell cycle. 40.7% of grade 10 students and 39.3% of grade 11 students believed that Anaphase was the longest phases of the cell cycle. This misconception probably arose from their biology textbook, instructional methods and teachers‟ explanation. The teacher should be active participation encouragement of students to understand the unfortunate terminology. It is important to remind students that many events critical to the cell cycle take place during inter phase and that the cell is metabolically active during this phase. 4.3. Observed Misconception Held by Students about Cell Biology and Cell Division Based on the analysis of cell biology and cell division diagnostic test of the students‟ (Table 7) 16 types of common misconception about cell biology and cell divisions were identified. The misconceptions were grouped into the five categories: definition of cell biology and cell division, types, energy, structure and functions and cell cycles (Table 8). 38 Table 8: Common misconceptions identified about cell biology and cell division in grade 10 and 11 students at KSPS. Percentage of students‟ common misconceptions G- 10 G-11 Categories of misconceptions Item f (%) f (%) Definition Cells are the building blocks of body. Cell division is the process of cells separation into many cells. 1 9 59.3 62.7 67.2 73.8 2 71.2 59 4 6 47.5 49.1 41 44.3 3 67.8 62.2 5 45.7 32.8 10 72.8 60.6 7 15.3 63.9 8 76.2 65.6 42.5 40.7 37.7 39.3 Structures and functions Both atoms and cells are made up of smaller parts including the nucleus. Nucleus center of holds all the supplies needed to make in the body. Chloroplast is the energy transformation center of cells. Centrioles are found in the nucleus of a cell. Types The differences between eukaryotic and prokaryotic cells are presence or absence of ribosomes. There is no cell division in plant cells but it occurs only in animal cells. The chromosome number is doubled in the Prophase of mitosis and halved in the Anaphase of mitosis. Mitosis and meiosis are function in an opposite and contrasting manner. Energy Very large cell has a larger surface area to volume ratio than a very small cell. Animal cells get energy for its function by synthesis of their own food. Cell cycles Chromosomes are formed as a result of shrinkage and thickening of spindle fibers. The organelles such as mitochondria and chloroplasts dissolve and vanish during cell division and then are reformed. DNA replication occurs in prophase during the process of cell 11 division. 12 Inter phase is the resting phase of mitosis. 39 4.4. Level of Students’ Misconception about Cell Biology and Cell Division The students‟ level of responses to the cell biology and cell division diagnostic test were ranked into three scales, zero to three levels as the criteria presented in table 9. The proportion of correct responses and misconception were determined by the analysis of 12 items (Appendix V) in the selected topics of cell biology and cell division. Students‟ misconception determined from the analysis of the cell biology and cell division diagnostic test are presented in table 7. Table 9: Criteria to analyze the cell biology and cell division diagnostic test items based on students‟ response First tier Second tier Response rank True response True reason T-T 3 False response True reason F-T 2 True response False reason T-F 1 False response False reason F-F 0 This criterion adopted from Odom and Barrow (1995) presented a table showing scoring on a two-tier test they developed for measuring college biology students‟ understanding of diffusion and osmosis. The two-tier diagnostic test was administered in the selected topics and the results were analyzed and presented in table 7. The proportion of correct responses and misconception were determined by the analysis of 12 question items (Appendix V) in selected topics of cell biology and cell division. The result in table 7 shows that the highest percentage of the respondents‟ response was observed in the T-F category in both grade 10 and 11 students, particularly the highest percentage of T-F category was observed in the test items 1, 2, 3, 7, 8, 9 and 10, respectively. Above 50% of the students answered under the category of misconception. On these items students had conceptual difficulties on the concepts. This indicated that the majority of the students‟ had high level of misconception about cell biology and cell division. Some difficulties in teaching cell biology and cell division that were identified in the classroom that the case includes vocabulary, unfamiliarity with cell structures and functions, teacher confusion, poor understanding of mitosis verses meiosis, 40 misunderstanding of chromosomes verses genetic information and the relationship between DNA, chromosomes, genes and chromatids (Atilboz, 2004). 4.5. Common Sources of Students’ Misconception about Cell Biology and Cell Division Data on students‟ misconception about cell biology and cell division, that teachers‟ respond, were collected through close-ended questionnaires described by means of three categories that was yes, no and not sure under listed the differ source of students‟ misconception of cell biology and cell division (Table 10). (Appendix IV). Table 10: Sources of Students‟ misconception as reported by teachers for close-ended question categories about cell biology and cell division. Teachers (N=3) responses Cell biology Cell division Yes No Not sure Yes No Note sure f (%) f (%) f (%) f (%) f (%) f (%) 1 2(66.7) 1(33.3) ___ 2(66.7) 1(33.3) ___ 2 1(33.3) 1(33.3) 1(33.3) 1(33.3) 1(33.3) 1(33.3) 3 1(33.3) ___ 2(66.7) 1(33.3) ___ 2(66.7) 4 2(66.7) ___ 1(33.3) 2(66.7) ___ 1(33.3) 5 2(66.7) 1(33.3) ___ 2(66.7) 1(33.3) ___ 6 1(33.3) 2(66.7) ___ 1(33.3) 2(66.7) ___ 7 1(33.3) 1(33.3) 1(33.3) 1(33.3) 1(33.3) 1(33.3) Items N- Number of teachers Based on the result (Table 10) in items 1, 4 and 5 above 50% of the teachers‟ reported that the major source of students‟ misconception about cell biology and cell division for both grade 10 and 11 students were biology text books, teachers‟ English language skills and biology instructional methods. Student‟s misconception about human physiology have been associated also with the way teachers and textbooks present the information and with incorrect use of language in class (Barrass, 1984). The low percentage of teachers‟ responded on the source of 41 students‟ misconception were biology teacher‟s guide, biology reference books and students cultural beliefs and practices. 4.6. Evaluation of Teachers’ Instructional Methods Used to Remediate Students’ Misconception about Cell Biology and Cell Division The findings of the study showed that biology teachers of the school were not considering the possible misconception that the students brought into the classroom and within the content they were teaching. Teachers have a very important role in realization of the correct education concepts. The educational approaches of today make emphasis on the student than on the teacher. According to Demirel, (2005), the student centered educational approach requires students to be more active in the classroom and participate at all levels. The misconception may be revealed during normal classroom discussions, in assignments or in test answer scripts and the teacher should organize effective teaching methods to overcome them. Oliver (1989) indicated that teaching approaches that are designed to remediate students‟ misconception can increases their understanding of concepts such as discussion, communication and reflection of meaning are essential features of successful approaches to resolve students‟ misconception. Clear, appropriate and achievable objective, facilitating classroom interactions, engaging students‟ in participation, relating concepts to students‟ experience, using active learning strategies and etc. are very important for teacher to teach and students to learn the topics of cell division and cell biology meaningfully. These instructional methods enable teachers to confirm the understanding of their students what they would teach about and their misconception. But, during classroom observations, the researcher observed that almost all these activities were not sufficiently implemented by biology teachers observed in the school. Students‟ interest, active participation, encouragement by the teacher and etc. are crucial to understand what was taught in the class and give a confidence for students to explain their idea without any hesitations in the classroom. These enable the teachers to probe what are the students‟ difficulty and their misconception. However, what actually observed in the classroom was that the students were silent and listens or follow their teacher what he or she was teaching passively and sometimes they answer the questions that are asked by the teacher. 42 Therefore, these approaches of teaching learning processes are ineffective in order to identify students‟ conceptual difficulty and to overcome their misconception about the topics of cell division and cell biology. Herron and Nurrenbern (1999) suggested that students should be allowed to express their own pre-concepts during a lesson or in the attempt to introduce new subject matter in a lesson and to let them be aware of inconsistencies regarding their ideas and the up to date scientific explanation. In this way, they can be motivated to overcome these discrepancies. Only when students feel uncomfortable with their ideas and realize that they are not making any progress with their own knowledge they will accept the teacher‟s information and thereby build up new cognitive structures. According to (Kose et al., 2006) that making use of different teaching strategies in classrooms positively affected the grade nine students‟ learning of concepts. In the biology student‟s textbook under the topics of cell division and cell biology there are different practical activities. All essential practical works were not taught by teachers theoretically or demonstrated practically for the students. This highly influenced student to understand the concepts of cell biology and cell division made the students to continue with their misconception about these topics. Skipping the practical works, which were included in the curriculum, makes the students failed to understand the concepts of cell division and cell biology. Probably these omissions of different practical works would affect students not to answer some items correctly in diagnostic test and held common misconception identified (Table 8). Besides, it may affect the subsequent learning of students. The teachers omitted many practical activities due to lack of laboratory facilities. The tendency of students to form relationship between newly learned concepts and previously learned concepts was important for conceptual understanding. Students should be given with sufficient opportunities to think about the daily lesson, to write down their thoughts and to discuss with their classmates. These enable them to apply what they had learned in earlier lesson to explain the phenomena, justify their own ideas, listen to their classmates‟ thinking, test the feasibility of the various explanations and reversed any disagreement (Hodson, 1993). In general, the observed classes of cell biology and cell division lessons showed that all biology teachers did not implement effective instructional methods to remediate students‟ misconceptions. 43 5. SUMMARY, CONCLUSION AND RECOMMENDATIONS 5.1. Summary The aim of the present study was to identify grade 10 and 11 students‟ misconception about cell biology and cell division using TTDT, identify the target concepts and propositional knowledge statements, sources of students‟ misconception, level of students‟ misconception and to evaluate the effectiveness of biology teachers‟ instructional methods to remediate students‟ misconception at KSPS, Ethiopian Somali regional state, eastern Ethiopia. The subjects of the study were 165 students (81 and 84 students from grade 10 and 11, respectively), selected using purposively and stratified systematic random sampling methods and all the biology teachers of grade 10 and 11 at KSPS were also involved in this study. A mixed probe design was employed in this research. Quantitative and qualitative data those were necessary for the study generated using interview, questionnaires, TTDT and classroom observations. The data collected was analyzed using quantitative and qualitative approaches to answer the research questions. TTDT prepared by the researcher was able to identify students‟ misconception about cell biology and cell division. By using this test, 16 types of common misconception about cell biology and cell division were identified and categorized into: definition of cell biology and cell division, structures and functions, types, energy and cell cycles. The content framework of the topics of cell biology and cell division was described through the review of grade 10 and 11 biology textbooks, teacher‟s guide and syllabi and prepared the target concepts and propositional knowledge statements. The researcher has identified two key concepts and 22 prepositional knowledge statements related to cell division, and three key concepts and 24 prepositional knowledge statements related to cell biology of grade 10 and 11 biology, respectively. The key concepts and prepositional knowledge statements were complete and sufficient to understand cell biology and cell division. The results also revealed that text books, teachers‟ English language skills and biology instructional methods were the major source of students‟ misconception about cell biology and cell division. The result showed that the majority of the students‟ had high level of misconception about cell biology and cell division. The instructional methods biology 44 teachers were implementing in teaching different concepts under the topics of cell biology and cell division were ineffective in order to remediate students‟ misconception. Teachers commonly used traditional instructional methods that were very difficult to find out students‟ conceptions. 5.2. Conclusions The findings of this study indicated that biology teachers did not consider the possible students‟ misconception within the lesson and not encourage their students in order to participate actively in the lesson. As a result, many students had difficulties of both content knowledge and concepts related to the topics of cell biology and cell division. So, in order to deal with students‟ misconception teachers, should carefully understand the existence of any misconception in different sub-topics of cell biology and cell division among students. Once students‟ misconception is identified, biology teachers could modify their method to remedy the problems by implementing alternative instructional methods that specifically address students‟ misconception. The instructional methods biology teachers implementing were ineffective to remediate students‟ misconception. Therefore, facilitating group discussions, encouraging students‟ participation, using active learning strategies, considering the possible misconception that the students brought into the classroom and within the content he or she teaching and etc are very important for teacher to teach and students to learn biology meaningfully and used to overcome students‟ misconception. The target concepts and the lists of propositional knowledge statements identified are complete and sufficient for understanding of the cell biology and cell division. They met the requirements of grade 10 and 11 biology syllabi on topics of cell biology and cell division the teachers should make the content analysis for the topics that contain the concepts difficult for understanding of the students. The findings of this study suggested that the two-tier diagnostic test of cell biology and cell division could be used for identification of students‟ misconception. Using these test sixteen common misconception those held by students were identified and classified into definition, structures and functions, types, energy and cell cycles of cell biology and cell division. This study revealed student has a series of 45 significant problems regarding the concepts of cell biology and cell division and structuring of such concepts in a meaningful manner. The students confuse the structures and functions of cells, stages of the cell division process and the events occurring at these stages with each other. 5.3. Recommendations The researcher recommended the following points that biology teachers should design the lesson based on students learning difficulties, the planner of the education should try his best to avoid learning difficulties, educational curriculum designers and stakeholders need to design the educational materials including active learning methods of instruction in the syllabi, different instruments such as worksheets including graphic presentations, conceptual problems and conceptual assignments help improve the instruction of cell biology and cell divisions. Biological science curriculum should be designed on conceptual change approach instruction to minimize students‟ misunderstanding in science, teachers should be aware of students‟ misconception and their harm to learning, teachers developing their instruction materials and planning, the teachers should be aware of students‟ misconception because teachers often suffer from the same misconception students have. Therefore, teachers should receive courses that can help them recognize and remediate their misconception, teachers should also be aware of several sources that may cause misconception and teachers should be careful in planning their lessons and their instructions in order not to let students for many misconception. Teachers may unwittingly transmit their misconception to the students. Thus, in addition to studying students‟ conceptual understanding on some concept area of biology further study could also be conducted to determine teachers‟ conceptual understanding. Due to limitation of resources, this research was restricted to only two grades (grade 10 and 11) levels. For further study, similar researches could be carried out for different grades levels and large sample size. Finally, continuous educational supervisions and on-job trainings for school biology teachers as well as fulfillment of the required educational facilities are recommended by the researcher. 46 6. 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Second, identify target concepts and propositional knowledge statements about cell biology and cell division and third, the draft of target concepts and propositional knowledge statements about cell biology and cell division were validated by two biology teachers. Part I, revealed there were two key concepts and 22 prepositional knowledge statements were indentified for grade 10 related to cell division and three key concepts and 24 prepositional knowledge statements were indentified for grade 11 related to cell biology. 1. Cell theory 2. Parts of cells and its functions. 3. Types of cells Each of these target concepts contained different propositional knowledge statements, for example, cell theory are: 1. All living organisms are composed of one or more cells, the cell is the most basic unit of life and all cells arise from pre existing living cells. 2. All organisms including animals, plants, fungi and microorganisms are made up of cells. 3. Cells vary in size, shape and specialized functions. 4. Most cells are so small that their details can be seen only with a microscope. 5. Living things can be made of just one cell to many millions of cells. 6. Some organisms are made of many types of cells and many of each type. 7. In single celled organisms such as bacteria, the single cell carries out all of the functions needed for the organism to stay alive; in organisms made of many cells individual cells work together with or depend on other cells to carry out their essential life functions. 55 Part II: Obtaining information about prior conceptions of students. This has been done through interview and open-ended questioners. Interview Semi-structured questions were designed based on target concepts that were explained in part Ito find out and grasp students‟ conceptions about cell biology and cell division. These questions were reviewed by three biology teachers for its validity. The researcher interviewed 8 students of the two grades level individually using open-ended questions. The interview took place in the students classroom where there was lit, silent and bright light. Students were asked each question in order by turn. The interview was lasting for 25 to 30 minutes for each question. When students got the questions very difficult the researcher provided additional information but also when students provided a wrong answer the researcher did not correct them. Besides, when the student‟s response was unclear follow up questions were used to elicit additional responses. In the interview, students were asked to answer the questions like what are the cells and cell division, what is the difference between cells and atoms, what are the difference and similarity between prokaryotic and eukaryotic cell, what are the difference and similarity between plant cell and animal cell, do other organisms make new cells? How do you know, what are the differences and similarities between mitosis and meiosis, among others questions (Appendix II). The responses obtained from interviews were analyzed and categories into correctly answered, partially answered, wrongly answered and students‟ misconception in such a way that they were used for preparing open-ended questions and for two-tier diagnostic test of cell biology and cell division. Open-Ended Questionnaire The open ended questionnaire was developed according to observed student response during the interviews and the related literature (Appendix III). Most of the questions were adapted from the items on the interview guide. The questions were administered in students‟ classroom where there was suitable situation that means bright light and no noise disturbance. The volunteers‟ teachers were assisted the researcher during the administration of the questionnaire. The time allowed to do the questions was 60 minutes. The responses of the 56 students were grouped under the following headings correctly answered, partially answered, wrongly answered, no answered and students‟ misconception. Part III: Preparation of cell biology and cell division TTDT. The content domain defined in part I and obtaining information about students‟ conceptions in part II was used to develop cell biology and cell division TTDT. The cell biology and cell division two tier-diagnostic test was prepared for identifying grade 10 and grade 11 students‟ misconception about cell biology and cell division. The test was designed using the data collected through interview and open-ended questionnaires. The distracters the second tier, for each item of cell biology and cell division two-tier diagnostic were based on students‟ interview and questionnaire data. All item stems were the similar stems on the open-ended questionnaire. Two-tier diagnostic tests are the form of multiple choice types of tests that consists of two-tiers or parts. The firsttier of each multiple choice item was consisting of content knowledge questions, it was designed to assess the students‟ knowledge about cell biology and cell division and having two to three choices and the second-tier of each multiple choice item was contain the reasons for selecting the responses to the first-tier and a set of four choices that are possible reasons for the answers given to the first part. The reasons consist of the designated correct answers together with the distracters that were identified by interview and open-ended questionnaires. The target concepts and the propositional knowledge statements were influenced the first-tier, where as the students‟ interview and open ended questionnaires responses were influenced the distracters of second tier of the item. Biology teachers and instructor of measurement and evaluation were validating all the items and confirmed that this was appropriate for grade 10 and grade 11 students in order to determine their understanding. Finally, test consisted of 12 items (Appendix IV). 57 7.2. Appendix II. Questions for Interview The main objective of this questionnaire is to gatherer data with regards to „„Students’ Misconception about Cell Biology and Cell Division’’ in the school. Your correct and complete response to the following questions will have great value for this study. So, you are therefore, kindly requested to reply all the items that request by the interviewee or researcher. Thank you in advance for your cooperation! 1. What is a cell? Explain in simple words? 2. What is the cell theory? 3. What is the difference between cells and atoms? 4. What are the difference and similarity between prokaryotic and eukaryotic cell? 5. What are the difference and similarity between plant cell and animal cell? 6. What is cell division? Explain in a simple word? 7. What are chromosomes? 8. During which phase of mitosis do chromosomes become shorter and thicker or condense? 9. When does DNA replication occur in a cell? 10. During which stage of the cell cycle does DNA replication occur? 11. Do other organisms make new cells? How do you know? 12. What are the differences and similarities between mitosis and meiosis? 13. How does your body make new cells? What would happen if new cells were not made? 14. Do your cells die? If so, how do you know and give an example of when they die? 15. What happens to the cell organelles during the cell division process? 16. How do the chromosomes act during mitosis and meiosis? 58 7.3. Appendix III. Open-ended Questionnaires The main objective of this question is to gatherer data with regards to “Students’ Misconception about cell biology and cell division’’ in the School. Your correct and complete answer to the following questions will have great value for this study. Therefore, you are kindly requested to answer all the questions after reading thoroughly. Thank you in advance for your cooperation! Direction: - 1. Do not write your name 2. Write your response in brief on the space provided. 3. Respond all questions precisely, clearly and genuinely. 4. Use English for your answer. Section 1:- Personal information 1.1. Name of school_______________________ Use (x) for sex 1.2. Sex Female ( ) Male ( ) Section 2:- Detailed information 1. Define a cell _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ 2. What is the difference between cells and atoms? _____________________________________________________________________ _____________________________________________________________________ 3. How many cells do you think you are made up of? Are they all the same?(Explain) _____________________________________________________________________ _____________________________________________________________________ 4. Define prokaryotic and eukaryotic cells? _____________________________________________________________________ _____________________________________________________________________ 5. What is role of nucleus in cells? _____________________________________________________________________ 59 6. Explain what is plant cell and animal cell? _____________________________________________________________________ _____________________________________________________________________ 7. What is the importance of Surface area to volume ratio in cells? _____________________________________________________________________ 8. Where do animal cells get energy for their function? _____________________________________________________________________ _____________________________________________________________________ 9. Where do plant cells get energy for their function? _____________________________________________________________________ _____________________________________________________________________ 10. What is the purpose of cell division? _____________________________________________________________________ _____________________________________________________________________ 11. Can your cells be repaired? Explain why or why not? _____________________________________________________________________ _____________________________________________________________________ 12. Define what is mitosis and meiosis? _____________________________________________________________________ _____________________________________________________________________ 13. Describe the structure of a chromosome? _____________________________________________________________________ 14. Do all of your cells contain DNA? If so, does each cell have the same DNA? Explain your reasoning. _____________________________________________________________________ _____________________________________________________________________ 15. Define what are chromosomes, genes and DNA. _____________________________________________________________________ _____________________________________________________________________ 60 7.4. Appendix IV. Close-ended Questionnaires These close-ended questionnaires were distributed to KSPS biology teachers. The main objective of this question is to gatherer data with regards to “Students’ Misconception about cell biology and cell division” in the School. Your correct and complete answer to the following questions will have great value for this study. Therefore, you are kindly requested to answer all the questions after reading thoroughly by making (x) in the box against the choice. (N.B Yes; No or Not Sure) Items No. Cell biology Major source of students‟ Yes No misconception 1 Biology textbooks 2 Biology teachers guide 3 Biology reference books 4 Instructional employed methods in teaching biology 5 Teachers‟ English language skills 6 Students‟ cultural beliefs and practices 7 Biology competency teachers‟ of subject matter 61 Not sure Cell division Yes No Not sure 7.5. Appendix V. Cell Biology and Cell division Diagnostic Test The main objective of this instrument is to gather data regards to “Students Misconception about cell biology and cell division” in the school. Your correct answer for the following questions will have great value for this study. Therefore, you are kindly requested to answer all the questions after reading thoroughly. Thank you in advance for your cooperation!!! Instructions: 1. Do not write your name 2. Choose the most suitable option and the reason for your choice in each question 3. Circle on the letter of your choice for first and second parts of questions. 4. If you feel that all options given are inappropriate, indicate the question (s) number and write down what you think the correct answer should be behind the question paper. Section 1:- Personal information Use (x) for sex Sex Female ( ) Male ( ) Detail Information: 1. What is a cell? A. contain hereditary information B. a structural and functional unit of life C. Living things can be made of just one cell to many millions of cells 1.1. Reason: 1.All cells are composed of complex molecules made by the cells themselves from simpler molecules (such as amino acids, simple sugars, and fatty acids) that enter the cells from outside the cells. 62 2. All organisms including animals, plants, fungi and microorganisms, are made up of cells 3. Most cells are so small that their details can be seen only with a microscope 4. Cells are the building blocks of body. 2. All matter, including cells, is made of atoms A. true B. false 2.2. Reason: 1. Both atoms and cells are made up of smaller parts, including the nucleus 2. Larger macromolecules such as proteins and carbohydrates are made of cells rather than atoms 3. Cells are made of molecules, molecules are made of atoms and atoms are the basic building blocks of ordinary matter. 4. Cells and molecules of protein are the same size. 3. Which of the following clues would tell you whether a cell is prokaryotic or eukaryotic? A. the presence or absence of a rigid cell wall B. whether or not the cell is partitioned by internal membranes C. the presence or absence of ribosomes 3.3. Reason: 1. Whether or not the cell carries out cellular metabolism 2. Whether or not the cell contains DNA 3. Prokaryotic cells lack any internal membranous compartmentalization 4. Presence or absence of ribosomes. 4. The role of nucleus in cells: A. absorb water from surrounding air B. gives off oxygen and taken in carbon dioxide C. controls and regulates the activities inside the cell 4.4. Reason: 1. Nucleus center of holds all the supplies needed to make in the body. 2. Nucleus contains the cell's genetic information 3. Nucleus controls the synthesis of ribosome‟s and proteins in the cytoplasm. 63 4. Nucleus contains the cell's hereditary information (DNA) and controls the cell's growth and reproduction. 5. Plant cells differ from animals cell is that; plant cells: A. plant cells have cell wall and chloroplasts B. plant cells are eukaryotic C. Plant cells are smaller than animal cells 5.5. Reason: 1. Animal cells break sugar into carbon while plant cells change carbon dioxide into sugar. 2. Structural support and protection of the cell and they make their own food by trapping sunlight for sugar. 3. No cell division in plant cells, it occurs only in animal cells. 4. Animal cells have rigid cells unlike Plant cells. 6. In which of the following structure of plant cells does photosynthesis take place? A. Mitochondria B. chloroplasts C. leaves 6.6. Reason: 1. The chloroplast of plants cell consists of stroma and grana where photosynthesis take place in: 2. in stomata of the leaves 3. in the xylem of the leaves 4. in the energy transformation center of cells 7. Surface area to volume ratio is important in cells: A. True B. False 7.7. Reason: 1. Very large cell has a larger surface area to volume ratio than a very small cell. 2. The efficiently the cell is in conserving energy. 3. The efficiently the cell is in obtaining oxygen it needs for respiration. 4. An increased surface area to volume ratio also means increased contact to the environment. 64 8. Where do animal cells get energy for its function? A. from the chemical bond energy in food molecules B. by synthesis their own food the process of photosynthesis C. from carbohydrates 8.8. Reason: 1. Animal cells make their own fuel molecules rather than plant cell. 2. Cells require a constant supply of energy to generate and maintain the biological order that keeps them alive. 3. Cells produced their own food by using carbon dioxide and water in the presence of sunlight and chloroplasts 4. Animals, in order to get fuel for our mitochondria, must eat plants 9. What is cell division? A. is the process that cells go through in order to develop. B. is the process of mitosis or meiosis. C. is a process in which, a large cell called the mother cell splits into two parts and each of the parts are called daughter cells. 9.9. Reason: 1. Cell division occurs in order for an organism to grow or repair damaged cells. 2. Cell division is important for reproduction and growth and repair damaged cells 3. Cell division is the way new cells are formed and a being is formed. 4. Cell division is the process of cells multiplication into many cells. 10. Which one of the following is true about mitosis and meiosis in cells? A. There is no difference between mitosis and meiosis in cells B. mitosis and meiosis in cells take place at different time C. In both processes cells divide 10.10. Reason: 1. Mitosis takes place within somatic cells and gamete cells 2. Meiosis takes place within only somatic cells 3. Mitosis takes place within somatic cells and Meiosis takes place within sex cells. 4. Mitosis and meiosis are function in an opposite and contrasting manner. 11. During which phase of mitosis does chromatin change to chromosomes? 65 A. Inter phase B. Prophase C. Metaphase 11.11. Reason: 1. Chromatin fibers become coiled into chromosomes with each chromosome having two chromatids joined at a centromere. 2. Chromosomes align at the metaphase plate at right angles to the spindle poles 3. DNA replication occurs in prophase during the process of cell division. 4. The paired centromere in each distinct chromosome begins to move apart. 12. What is the longest phase of the cell cycle? A. Anaphase B.G1 phase in mitotic C. Inter phase 12.12. Reason: 1. In mitotic cell division cycle, the longest phase is G1 phase which lasts for 10 hours. 2. Inter phase is the longest phase in the cell cycle lasting 18 of the 20 hour cycle. 3. Anaphase is usually the longest because the cells are always working, getting work done, and moving. 4. Inter phase is the resting phase of mitosis. 66 7.6. Appendix VI. Classroom Observation Checklist The main purpose of this classroom observation is to evaluate the effectiveness of grade 10 and 11 biology teacher‟s instructional strategies in overcoming “Students Misconception about cell biology and cell division” in the school. Name of school ________________________________ Title of the daily lesson_________________________ Name of teacher________________________________ Class observed_________________________________ Observer (Researcher) __________________________ Number of students present during observation___________ Day of observation_____________ 67 Focal for points Specific points of observation observation Instructional approach used by the teachers Yes The teacher Lecture points without focus on the students‟ misconception Elicit students‟ pre- knowledge prior Instruction Encourage students to identify their Misconception Present contents in a variety of ways Evaluate students progress toward achieving conceptual change Students‟ awareness about misconception present inquiry questions to elicit students‟ prior conception Provide a forum for students to confront their misconception Instructional material or Textbook Implementation Based on misconception approach · Scope of subject matter is narrow and · Do not include misconception 68 No 7.7. Appendix VII. Target Concept and Propositional Statements of Cell Biology and Cell Division Part I. The target concepts of the content domain of cell biology for grade 11 biology textbook and syllabus include: 1. Cell theory 2. Parts of cells and its functions. 3. Types of cells The propositional knowledge statements of the above target concepts are: 1. All living organisms are composed of one or more cells, the cell is the most basic unit of life and all cells arise from pre existing living cells. 2. All organisms including animals, plants, fungi and microorganisms are made up of cells. 3. Cells vary in size, shape and specialized functions. 4. Most cells are so small that their details can be seen only with a microscope. 5. Living things can be made of just one cell to many millions of cells. 6. Some organisms are made of many types of cells and many of each type. 7. In single celled organisms such as bacteria, the single cell carries out all of the functions needed for the organism to stay alive; in organisms made of many cells individual cells work together with or depend on other cells to carry out their essential life functions. 8. In multi cellular organisms the structures that make up those organisms including brain, muscles, skin and lungs in animals and stems and flowers in plants are made up of cells. 9. All cells are composed of complex molecules made by the cells themselves from simpler molecules such as amino acids, simple sugars and fatty acids that enter the cells from outside the cells. 10. In multi cellular organisms cells provide structural support for the organism they are part of and carry out essential life functions for that organism. 11. In cells of plants and animals there are internal structures that perform specialized functions such as extracting energy from food, making new molecules for growth and eliminating wastes. 69 12. In addition to the internal structures that perform specialized functions for cells the interior of cells is also filled with water and molecules that are dissolved in that water. 13. A membrane makes up the outer surface of a cell which controls what enters and leaves the cell. For example, small molecules such as amino acids, fatty acids and simple sugars can enter and leave through the cell's membrane. 14. Many of the same basic life processes such as extracting energy from food making the materials needed for their own growth and eliminating wastes take place within the individual cells of all organisms including plants, animals, fungi and microorganisms. 15. Plant and animal cells need molecules from food, water, oxygen and a way to eliminate wastes in order to continue to function. 16. Bacteria need molecules from food, water and a way to eliminate wastes to continue to function. Some bacteria need oxygen and others do not. 17. The different body structures of plants and animals including brain, muscles, skin and lungs in animals and stems and flowers in plants are made up of different types of cells. 18. Different body structures are made up of different types of cells. 19. There are many different types of cells in terms of size, structure and function. All cells have certain characteristics in common 20. The different types of cells that make up the body parts of animals develop from one single cell. 21. The different types of cells that make up the body parts of plants can develop from one single cell. 22. Cells in repeatedly divide to make more cells for growth and repair and for reproduction. 23. Groups of cells work together to perform specialized functions in multi cellular organisms. These include red blood cells which carry oxygen to all cells of the body, muscle cells, which allow movement of the organism and nerve cells which transmit electrical signals between the brain and the rest of the body. 24. In multi cellular organisms, new cells needed for growth and repair come from the division of existing cells. 70 Part II. The target concepts of the content domain of cell division for grade 10 biology textbook and syllabus include: 1. Types of cell divisions: Mitosis and Meiosis 2. Chromosomes and genes The propositional knowledge statements of the above target concepts are: 1. Cell division is the process where a single living cell splits to become two or more distinct new cells. 2. Cell division has three main functions the reproduction of an entire unicellular organism, the growth and repair of tissues in multi cellular animals and the formation of gametes or eggs and sperm for sexual reproduction in multi cellular animals. 3. The growth of a fertilized embryo is accomplished through the division and differentiation of cells and while some cells such as skin cells divide almost continuously after birth other highly specialized cells such as some neurons do not and cannot be replaced after disease or injury. 4. Cell division results in the formation of two nearly identical cells from a single original cell. 5. Individual cells grow by creating new complex molecules that make up the cells‟ structures using molecules from food that enter the cells. 6. In multi cellular organisms both an increase in individual cell mass and an increase in cell number cause the organism of which they are part to increase in size and mass. 7. The successive duplication of cells explains how multi cellular organisms can develop from a single cell. 8. Cell cycle focuses on mechanisms that regulate the timing and frequency of DNA duplication and cell division. Cell cycle is defined as the period between successive divisions of a cell occur through a series of changes identified as prophase, metaphase, anaphase and telophase. 9. Cell cycle is the sequence of events by which a cell duplicates its genome synthesizes the other constituents of the cell and eventually divides into two daughter cells. 10. The cell cycle or cell division cycle is the series of events in a eukaryotic cell between one cell division and the next. Thus, it is the process by which a single cell fertilized 71 egg develops into a mature organism and the process by which hair, skin, blood cells and some internal organs are renewed. 11. The two forms of cell division mitosis and meiosis are the biological mechanism by which the principles of heredity and evolutionary theory are realized. 12. Mitosis is simple cell division that creates two daughter cells that are genetically identical to the original parent cell. 13. Mitosis begins with replication of the DNA within the cell to form two copies of each chromosome. Once two copies are present the cell splits to become two new cells by cytokinesis or formation of a fissure. 14. Mitosis occurs in most cells and is the major form of cell division. 15. Meiosis is the production of daughter cells having half the amount of genetic material as the original parent cell. Such daughter cells are said to be haploid. 16. Meiosis occurs in human sperm and egg production in which four haploid sex cells are produced from a single parent precursor cell. 17. In both mitosis and meiosis of nucleated cells shuffling of chromosomes creates genetic variation in the new daughter cells. These important shuffling processes are known as independent assortment and random segregation of chromosomes. 18. Cell division is a very important process in all living organisms. During the division of a cell DNA replication and cell growth also take place. All these processes that means cell division, DNA replication and cell growth hence, have to take place in a coordinated way to ensure correct division and formation of progeny cells containing intact genomes. 19. Chromosomes are organized structures of DNA and proteins which contains many genes regulatory elements and other nucleotide sequences. 20. A gene is the basic physical and functional unit of heredity. 21. Genes are made up of DNA act as instructions to make molecules called proteins. 22. Genes carry the information that determines your traits which are features or characteristics that are passed on to you or inherited from your parents. 72 7.8. Appendix VIII. Response of Students for Interview Questions Categories of students‟ response Items Correctly Answered Partially Answered Wrong Answered 1 -Cell is the basic -cells are so small -Cells are small building block of all that their details microscopic living things. can be seen only organisms. Cell is a structural and with a microscope functional unit of life. Cells vary in size, shape and specialized functions. 2 -Cell theory is the -The cell is the -Cell theory is theory says that unit of structure, that study about everything that is alive physiology and plant cell and is made up of cells. organization in animal cells. Cell theory says that living things. all things start with cells as their basis. Cells a rises from existing cells. 3 ___________ 4 __________ -These larger building blocks, made up of atoms, combine in very specific ways to form a cell. -Eukaryotic cells have a nucleus while Prokaryotic cells don't Eukaryotic cells include animal cells Prokaryotic cells are mainly bacteria 73 Misconception -Organisms contain Cells are building block of body. ___________ -Cells are the smallest and most fundamental building block of materials. -Cells and atoms are the same because both of them contain nucleus. -Prokaryotic cells are multi-cellular always and eukaryotic cells are often unicellular. -Both eukaryotic and prokaryotic cells are whether or not the cell carries out cell division. 5 6 7 8 9 10 -Both plant and animal cells have the nucleus, mitochondria, ribosome‟s, vacuoles and Golgi-bodies and endoplasmic reticulum. But plant cells possess cellulose cell wall but not animal cell, plant cells have large vacuole compared to the animal cells. -Cell division is the process by which a parent cell divides into two or more daughter cells -Plant cells are larger than animal cells. Plant cells have chloroplasts unlike animal cells Plant cells have a cell wall unlike animal cells. -Chromosomes are a thread like linear strand of DNA and associated proteins in the nucleus of eukaryotic cells and circular strand of DNA in bacteria that carries the genes. -Prophase -Chromosomes are organized structures of DNA and proteins that are found in organism. -DNA replication occurs whenever cells need to replicate. Before a cell can divide it needs another copy of its genome for the second cell that will be produced. -The inter-phase of cell cycle has 3 stages: G1, S, and G2 phase. The replication of the DNA occurs during the S phase. -When DNA is damaged and one strand of the damaged area is ___________ replicated after the damage is removed. _________ ___________ -Inter phase -Animal cells have a cell wall and cell membrane, plant cell only have cell membrane ____________ -Cell division is when two parent cells divide into two cells and are able to fully function and different from the normal cells. Chromosomes are the complex of DNA and protein found inside the nuclei of eukaryotic cells. -Cell division is the process of cells separation into many cells. -Inter phase ______________ -Both chromosomes and chromatin are the same. ___________ -Anaphase __________ 74 11 12 13 -Yes. Because the process of cells Growth, Maintenance and Repair -Both are forms of cell division. It takes one cell and makes it into multiple cells, allow for replication. But mitosis takes place within somatic cells but Meiosis takes place within gamete cells, in mitosis. -New cells are created by cell division. This is beneficial for the organism because cells do die and need to be replaced. 14 -Yes, a cell can die in many ways through infection, poisoning, overheating or lack of oxygen 15 -During cell division nuclei separating; but they never show the mitochondria, endoplasmic reticulum, or other organelles replicating in the process. -Cells in tissues die and need to be replaced. Tissues may be damaged and new cells repair that damage. -Mitosis is asexual and it‟s just duplication of one set of chromosomes. Meiosis is sexual reproduction and it involves two sets of chromosomes. -No. An organism does not make new cells. -Cell division, The cell would physically be unable to survive as a consequence The organism will be dying -May damage surrounding cells. But there is another, tidier way to go programmed self destruction, or apoptosis. -Cells use organelles, such as the endoplasmic reticulum and P granules, as vectors for the segregation of information. -The bodies are -If the cells are not making new dying the cells. organism will be dying but the cells are not replaced. 75 __________ -Mitosis or meiosis is the process of living cells go through a series of stages. -Mitosis and meiosis are function in an opposite and contrasting manner. -No -Yes, but the cells are dying during the organism die. -Nothing happened to organelles during cell division. -The organelles, such as mitochondria and chloroplasts, dissolve and vanish during cell division and then are reformed. 16 _________ -Chromosomes are condensed into compact forms for handling. Since the chromosomes are replicated before going into either meiosis or mitosis. 76 -During meiosis Sister chromatids are pulled to the opposite poles and one diploid cell has become two diploid cells. -In both case the chromosomes act the same thing and the same action. The chromosome number is doubled in the Prophase of mitosis and halved in the Anaphase of mitosis. 7.9. Appendix IX. Response of Students for Open-ended Questionnaires Items 1 Correctly Answered -Cells are structural and functional unit of life. -Cells are so small that their details can be seen only with a microscope. 2 -cells are the basic unit of life but atoms are building blocks of everything including cells. 3 -Our body made up of a billion of cells and they are not the same for example, there are nerve cells, muscle cells, blood cells etc. 4 - Both have DNA as their genetic material, membrane bound and have ribosomes. - eukaryotes have a nucleus, while prokaryotes do not Categories of students‟ response Meaningless Wrong Answered Answered -cells are a process -living things can that gives our body be made of just in many important one cell. things. -cells are -cells are personal microscopic functions that organism. contain unicellular and multi cellular cells. -cells are the unit - Cell is a tissue function but atoms and atom is are the smallest we indivisible. can‟t see by eyes. -all matters including cells made up of atoms. -cells are made up -cells are made up of smaller parts of one or more including the cells and they are nucleus not the same. -animal cells and -they are single plant cells. cells and multi -I have a billion of cells but not the cells they are not the same. same. -prokaryotic cells are bacteria. -Eukaryotic cells have a nucleus while Prokaryotic cells don't have. 77 - The difference between Prokaryotic cells and Eukaryotic cells are the presence and absence of ribosomes. Misconception -Cells are the building blocks of body. -Cells and atoms are the same because both of them contain nucleus. -we are made up of a billion of cells but all are the same cells. -Both eukaryotic and prokaryotic cells are whether or not the cell carries out cell division. 5 -controls and regulates the activities inside the cell. -Nucleus contains the cell's hereditary information (DNA). -Nucleus controls…. - Nucleus center of metabolism. - Nucleus regulates the body. - absorb water from surrounding air - gives off oxygen and taken in carbon dioxide. 6 -animal cells do not have a cell wall or chloroplasts but plant cells do. -Animal cells are round and irregular in shape while plant cells have fixed rectangular shapes. -For cells are in obtaining oxygen it needs for respiration. -Plant cells have rigid…………… -have cellulose in cell wall. -Cells smaller in size. -Animal cells have rigid cell walls unlike plant cells. -Animal cells _____ larger in size than plant cells. 7 8 9 10 11 -The rate of diffusion depends on factors. -Cells require a constant supply of energy to generate -From the chemical -Food by using bond energy in food carbon dioxide. molecules. -Fuel for our mitochondria. -Manufacturing their food by photosynthesis. -All green plants are producing their own food. -For reproduction and growth and repair damaged cells. -Yes. Because the process of cells Growth, -Cell uses the energy it releases in respiration. -Cell releases energy in respiration. -Animal cells make their own fuel molecules rather than plant cell. -Plants get their -from their parts food. means from leaf. - Photosynthesis of -plants get their plants. food from living -food very thing. important. -The process of -The process that mitosis. cells go through -The nucleus splits in order to and DNA develop. -The mother cell splits into parts -Cells in tissues -No. An organism die…. does not make -Need to be new cells. 78 - Nucleus holds all the materials needed to make every cell in the body. -Nucleus center of holds all the supplies needed to make in the body. -For cells are in conserving energy. -By production their own food the process of metabolism. ____ -For the process of cells multiplication into many cells. -The organism will be dying but the cells are 12 • Maintenance and Repair -Meiosis produces daughter cells that have one half the numbers of chromosomes. -Mitosis is asexual and it‟s just duplication of one set of chromosomes. 13 -Filamentous bodies which are typically present in the nucleus and which become visible during cell division. 14 -Yes. -All cells contain the same DNA. - But is that not every gene that is encoded by the DNA is expressed in every cell. 15 -Genes are packaged in bundles called chromosomes -A gene is a distinct portion of a cell‟s DNA. -DNA carries the genetic information in the body‟s cells. replaced not replaced. - Meiosis organisms to reproduce -Meiosis is reproduction two of chromosomes. - Mitosis takes place within -Mitosis and meiosis are function in an opposite and contrasting manner. -Meiosis occurs in the reproductive cell -units of heredity Chromosomes are -Chromosomes -is made up of really made up of and chromatids long chains chromotid. are essentially the same thing. - Chromosomes are formed as a result of shrinkage and thickening of spindle fibers. -No -Yes -The cells become specialized… -b/c cells express a set of bone….. -Mitosis is sexual reproduction. -Meiosis is asexual reproduction -No -All cells contain the different DNA. - Because cells are concerned all of these tissues etc have a function. - Chromosomes are - DNAis coded thread …… instructions for - Chromosome is making long chain. everything the -Genes are heredity body. -DNA double - Chromosomes structures. are chains of chemical building blocks. 79 -No - Because if our cells are the same. Cells contain the same DNA. ____