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Patty McCarrin Cory Redding Biology Lesson July 20, 2004 Audience- Cory Redding Eighth Grade Physical Science- William Allen Middle School, Moorestown, New Jersey There are approximately 24 eighth grade students in each of my five eighth grade physical science classes. The classes meet for 45 minutes daily. Students are not tracked by academic ability, but instead grouped heterogeneously. One of the five classes is an inclusion class in which there are special education students mainstreamed with regular education students. The special education students range from auditory impaired to attention deficit disorder. There is a support teacher in that class who modifies tests and provides the students who have IEPs specifically for science with additional support. There is also an interpreter who signs for four auditory impaired students. The environment of each of the classes is one of excitement, energy and positive attitudes. Each of the five classes learns the same subject matter. The students are on task and focused for the majority of the class period. They enjoy coming to science class and are most eager to learn when a hands-on activity is taking place. Students are often required to relate their findings to the real world, and specifically their lives. They are enthusiastic about discussing topics that they can connect with. Students are often asked to think critically and apply higher order thinking skills. It is frequently required that students explain why scientific phenomena occur. Seldom are students asked to memorize facts but instead they must apply scientific concepts to prove mastery of content. Student expectations range from designing and implementing their own experiments using the scientific method to conducting teacher designed guided activities to participating in a classroom discussion. A driving, or essential, question is presented to the students at the beginning of the investigation and the teacher refers back to that question throughout the related activities. An evaluation may simply be to answer, in detail, the driving question at the end of the lesson. Identify an area of biology that you know is frequently difficult for students The function of biological polymers is affected by its make up. Enduring Understanding We can understand biological phenomena by analyzing them at multiple levels from the molecular to the organism level. Standards: Content Standard A • Use appropriate tools and techniques to gather, analyze and interpret data. • Develop descriptions, explanations, predictions and models using evidence. • Think critically and logically to make the relationships between evidence and explanations. Content Standard B • Students observe and measure characteristic properties and use those properties to distinguish and separate one substance from another. Content Standard C • Living Systems at all levels of organization demonstrate the complementary nature of structure and function. • Disease is a breakdown in structures or functions of an organism. Some diseases are the result of intrinsic failures of the system. Background Content and Discussion of Pedagogic Literature Biologic Polymers Teacher Background Information Polymers are made up of monomers. The three main types of biologic polymers are proteins, polysaccharides and nucleic acids. Lipids are not considered polymers because they are not composed of component part molecules (Krough, 2005). Proteins Proteins accomplish a multitude of functions within the body and are often referred to as building-block molecules. They are made up of monomers called amino acid joined together by polypeptide bonds. Amino acids have a typical structure, consisting of a carbon atom in the middle with an amino group on one side, a carboxyl group on the other and a hydrogen atom attached to the “top.” What differentiates one amino acid from the other is the side-chain, or “R” group. The variation in the R position results in twenty different amino acids. www.hcc.mnscu.edu/.../ amino_acid_structure_2.jpg Whilst the protein is forming and monomers are lined up in a chain, the correct terminology is a polypeptide. Once the polypeptide is folded, it is considered a protein. Below is a diagram of how a protein is synthesized. www.accessexcellence.org/ RC/VL/GG/images/protein.jpg The shape of the protein is imperative to its function. Should the protein be folded incorrectly due to a mutation, such as the process that occurs in sickle cell, the protein will not function properly. Proteins are responsible for a variety of functions, including movement, chemical processes within the body and mechanical support. Polysaccharides Polysaccharides are made up of monomers called monosaccharides, or simple sugars. Examples of monosaccharides are glucose and fructose. When the monosaccharides link up, a polysaccharide, or complex carbohydrate, is formed. Polysaccharides are carbohydrates that are polymers. There are four main types of polysaccharides are starch, glycogen, cellulose and chitin. Polysaccharide Starch Glycogen Cellulose Chitin Function Store carbohydrates in plants Store carbohydrates in animals Helps forms cell walls Structure May be Found in… Potatoes, wheat grains Pasta Trees, grass External skeleton of arthropods www.ualr.edu/botany/ polysaccharides.jpg Nucleic Acids Nucleic acids are made up of monomers called nucleotides. Each nucleotide includes a phosphate group, a sugar and nitrogen base. When nucleotides are linked together, nucleic acids such as DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are formed. There may be up to three billion nucleotides linked together to form a copy of DNA in humans, and one copy exists in each of our cells (Krough, 2005). The function of DNA is to store our genetic information. RNA’s functions include aiding in the synthesis of proteins and transporting encoded DNA (see figure 1.1). www.accessexcellence.org/RC/VL/GG/images/rna.gif Sickle Cell Anemia Teacher Background Information Sickle cell anemia is a blood disorder that primarily affects people of West African descent. It is an autosomal recessive disorder, meaning that children that receive two copies of the gene will have the disease. Children that inherit only one copy of the gene will be carriers but generally do not exhibit symptoms. In an area where malaria is common this is an advantage because having the genetic mutation helped protect people from getting infected with malaria. Unfortunately over time individuals with the heterozygous recessive gene married others with the same recessive trait. The recessive form of the gene became much more common and more and more people inherited the disease. Sickle cell anemia is caused by a genetic change in hemoglobin. Hemoglobin is a protein that is made up of chains of amino acids. Its function is to pick up oxygen in our lungs and deliver it to other cells. It performs this function well unless it is inherited in another form called hemoglobin S. Hemoglobin S results from a change in one nucleotide that makes up the DNA. The mRNA transcribes the incorrect information and carries it to the tRNA. In turn, the tRNA will translate and drop off the incorrect amino acid which forms the polypeptide. This results in a change in the fold of the protein. Glutamic acid, which is polar and soluble in the watery cytoplasm of the red blood cell, is replaced by valine which is non-polar and non-soluble in the cytoplasm. The valine stacks and precipitates out in spike like formation. The result of this process is a sickle shaped cell as opposed to the concave discs that are normally found. Because the capillaries are so tiny, they can become clogged when the odd shaped cells attempt to pass through them. This can cause pain and damage to tissue and organs. Sickle cells also have a shorter life span than regular blood cells which can cause chronic anemia. The severities of the symptoms of the disease vary from individual to individual. They cannot be predicted based solely on genetic inheritance. Some develop life threatening symptoms as infants but others have only mild symptoms throughout their life. Varying severity of the symptoms can be exhibited at different times. Factors that can cause the disease to manifest itself are low oxygen, cold temperatures and dehydration. “There are several symptoms that warrant immediate medical attention, including the following: • • • • Signs of infection (fever greater than 101°F or 38.3°C, coughs frequently or breathing trouble, unusual crankiness, feeding difficulties) Signs of severe anemia (pale skin or lips, yellowing of the skin or eyes, very tired, very weak) Signs indicating possible dehydration (vomiting, diarrhea, fewer wet diapers) Other signs (pain or swelling in the abdomen, swollen hands or feet, screams when touched). Testing can be done to determine if a child has sickle cell disease even before the child is born. The disease cannot be cured but some of its effects can be mitigated. Preventive antibiotics are used, making sure that a person stays hydrated is important, getting proper immunizations, avoiding stress, and proper nutrition are important.” http://health.enotes.com/genetic-disorders-encyclopedia/sickle-cell-disease Goals of Lesson Big Ideas • There are polymers in our body that perform specific functions. • The biological polymers need to have a certain make up to perform their function. • Changing a structure on the molecular level influences an organism at the organism level. Objectives • The students will identify the three main types of biological polymers and their functions. • The students will be able to identify the effects of change in a polymer at the molecular level and how it may influence the organism at the whole body level. Students’ Prior Knowledge Students have been learning about polymers over the course of six days. The lesson on biological polymers and the effect of their make up on function will occur on day seven. Prior knowledge from the polymer unit includes: ~ What is a monomer? ~ What is a polymer? ~ Examples of common/ everyday polymers ~ Synthesis / cross-linking of polymers ~ Models of monomers/ polymers (using paper clips) Introduction to Polymers ~ Fortune Telling Fish ~What is a monomer? ~What is a polymer? ~ Examples of Common Polymers Using the Internet to Investigate Polymers (Plastics) Eighth Grade Polymer Unit Playing with Playing with Polymers Polymers (Synthesize and ( Synthesize and Collect Data for Collect Data for Polymer #1Polymer #2Gloop) Ooblec) BIOLOGIC POLYMERS ~ Polymers in my Body! ~ How can a change in the make up of a polymer affect its function? Playing with Polymers ( Synthesize and Collect Data for Polymer #3Goobers) A Molecular Model of Polymers (Paper Clips and Cross Linking) Review Polymers Discuss Homework (Explain how the change in the make up of a polymer effect its functiondiseases) Dr. Dad Video Polymer Quiz Students also have background knowledge from the seventh grade life science course. A short review will take place at the beginning of the lesson to activate concepts learned the year before. Prior knowledge includes: ~ Structure of the cell ~ Basic understanding of human body systems ~ Amino Acids/ Proteins (transport, enzymes etc) ~ Monosaccharides/ Polysaccharides (starch, glycogen, etc) ~ Nucleotides / Nucleic Acids (DNA, RNA, etc) ~ Molecules Part 1 – Identifying Biologic Polymers Hook and Informal Pre-Assessment – Hand out worksheet with a list of various substances. Have students circle any substance that contains or is a polymer. (see attached student worksheet) Students will work in groups of three and list as many examples of monomers and polymers in their body as they can. Students will have resource books and web sites to use that include information that will give examples of monomers or polymers in the body. Suggested web site: http://pslc.ws/mactest/maindir.htm Expected Student Responses Polymers Monomers Amino acids Sugar (glucose, fructose) Protein Polysaccharides (starch, glycogen, cellulose) Nucleic Acid (DNA, RNA) Nucleotides (sugar, phosphate, base combination) Students will take on the role of one biologic polymer (protein, polysaccharide, nucleic acid) and will be responsible for finding examples of their polymer along with its function. (see attached student worksheet) Expected Student Responses Protein Function Transport Move other molecules Enzymes Quicken Chemical Reactions Hormones Chemical Messengers Structural Mechanical Support Contractile Movement Polysaccharides Glycogen Chitin Nucleic Acid DNA mRNA tRNA Examples Hemoglobin: Transports oxygen through the blood Sucrose: Positions sucrose (table sugar) so it can be broken down. Growth Hormone: stimulates growth of bones Keratin: Hair Collagen: Cartilage Myosin and Actin: Allow muscles to contract Function Carbohydrate storage in animals External skeleton of anthropods Function Stores genetic information Transmits information encoded in DNA Uses the information of mRNA to make proteins Jig Saw Activity - Students will share information with original group. To insure all students have accurate and complete information teacher will fill out data table on overhead. Part 2 – Effects of a Change in a Polymer at the Molecular Level Students are asked to take out their chart with information on the properties of the three polymers that they synthesized and investigated at the start of the unit. Students will be asked to briefly review the characteristics of the polymers. Students will be given the specific ingredients for one of the polymers (gloop) and asked to make changes in the ingredients following the guidelines outlined on the student worksheet. Students will list any changes in the characteristics of the polymer. (see attached worksheet) Teacher will call students together and they will share the results of their investigation. List quantitatively the results of the slime test and the bounce test. Discuss the changes that were made to get these results. (i.e. what were the specific ratios and proportions used to get new characteristics) Students will get into groups of four and asked to research sickle cell anemia using web sites, books, or articles. Each group will be responsible for researching one of the following questions: What is sickle cell anemia? What causes sickle cell anemia? What effects does sickle cell anemia have on your body? How do you get sickle cell anemia? Web Articles: http://kidshealth.org/teen/diseases_conditions/blood/sickle_cell_anemia.html http://www.mayoclinic.com/health/sickle-cell-anemia/DS00324 http://www.nhlbi.nih.gov/health/dci/Diseases/Sca/SCA_All.html http://www.scinfo.org/Sickleinfosheet2.doc http://www.scinfo.org/powerpt.htm (on line power point presentation) Jig Saw 2 - Students will meet with representatives to share what they learned with the other groups. Finally, as a whole group we will discuss the findings and how they relate to the polymer investigations. Teaching Points • • • • • Polymers are made up of smaller components called monomers. There are three main types of biological polymers. The make up of biological polymers determine their function. A change in one nucleotide (monomer) that makes up the DNA (polymer) leads to the incorrect transcription from the mRNA (polymer) to the tRNA (polymer.) The tRNA translates and delivers the incorrect amino acid (monomer) which forms the polypeptide. This results in a change in the fold of the protein (polymer.) The properties of anything made out of polymers really reflect what's going on at the ultratiny (molecular) level. So, things that are made of polymers look, feel, and act depending on how their atoms and molecules are connected, as well as which ones we use to begin with! Connection to Enduring Understanding • • • • Molecular Level – Polymer make up can cause a malfunction in a structure. Cellular Level – Red blood cells are sickle shaped as a result of incorrect make up. Sickle cells expire more quickly due to shape. Tissue/System – Circulatory system malfunctions because the capillaries become clogged with the sickle shaped cells. Whole Body Organism – painful, causes damage to tissues and organs, premature death rate. Assessment and Homework – Differentiated Expectations Lower Level Explain how a change at the molecular level (gene mutation) may affect an organism at the whole body level. (Effects of sickle cell anemia on the body) Middle Level Research Tays Sachs disease or Hemophilia. Explain the causes of the disease and how it affects the body. Gifted Research Tays Sachs disease or Hemophilia and compare their genetic mutations with sickle cell anemia. Name: ________________________________ Date: ____________ Period:_____ Biological Polymers Directions: Assign each student in your group one of the three main types of biological polymers (protein, polysaccharide, nucleotide) and break up into new groups with other students who were also assigned that polymer. After filling in the correct information below, you will come back to your original group to teach the other group members about the biological polymer you researched. Proteins: Look at the list of the specific types of proteins below. For each of the specific proteins, explain the function and an example. Protein Transport Enzyme Hormones Structural Contractile Function Polysaccharides: What is the function of Glycogen? What is the function of chitin? Nucleotides: What is the function of DNA? What is the function of m-RNA? What is the function of t-RNA? Example Effects of a Change in a Polymer at the Molecular Level Directions: Look at your polymer data table, specifically POLYMER #1. Briefly discuss the characteristics (bounciness, slime rating, etc) of that polymer with your group. Following the below guidelines, create a different polymer using the same ingredients that you used to synthesize POLYMER #1. Guidelines: You may use any amount of white glue between 1mL and 20 mL. You may use any amount of sodium borate solution between 1mL and 20 mL How much glue did your group decide to use? _________mL How much sodium borate solution did your group decide to use? ___________mL List the characteristics of your new polymer: Characteristic Description Slime Rating Slow Poke Test Quick Poke Test Slow Pull Test Quick Pull Test Blob Test Hang Test Bounce Test Newly Synthesized Polymer Questions: How did changing the amount of glue and sodium borate solution change the characteristics of your newly synthesized polymer? What is the ratio of the original amount of glue to the new amount of glue? ___________:_______________ What is the ratio of the original amount of sodium borate solution to the new amount of sodium borate solution? ___________:_______________ Group _______________________________ Date ______________________ _______________________________ Period_____________________ _______________________________ _______________________________ Sickle Cell Anemia What is sickle cell anemia? What causes sickle cell anemia? What effects does sickle cell anemia have on your body? How do you get sickle cell anemia? Name: ________________________________ Date: ____________ Period:_____ Circle the items that are polymers in red! Circle the items that contain polymers in black! If the item is not a polymer or does not contain one cross it out! Wood, Food, Rubber, Water, Plastic, Bottles, Styrofoam, RNA, Chewing Gum, Latex Paint, Cellulose, Trees, Bugs, Humans, Cows, Shoes, Whales, Walruses, Fungus, Crabs, Lobster Shell, Plants, Silk, Wool, Bullet, Polysaccharides, Proof Vests, Tires, French Fries, Rubber Bands, Foam, Amino Acids, Nucleotides, DNA, Chitin, Sugar, Nucleic Acid Pictures: http://srs.dl.ac.uk/Annual_Reports/AnRep02_03/cd12-fig3.jpg http://polymers.case.edu/images/dna.jpg