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Cell Life Cycle and Reproduction (Mitosis & Meiosis) Name__________________________________________ assign.#_ __ Notes Unit Goals: • Describe the phases of the cycle. • Describe the process of . – Describe the functions of mitosis. Unit Goals: • Describe the process of . – Describe the functions of meiosis. – Explain the consequences of mistakes. ***Why not just one large cell? Difficult to get ___________________ in and waste out. S phase- DNA synthesis The Cell Cycle • • • • • Chromosomes _________________. Chromosomes are inherited genetic information Chromosomes are made up of _____________. Can only be seen when cells are _____________. Chromosomes ____________ -or copy is made • The two copies are -_____________ together at a point called a _____________. -are called sister _____________. G1 phase Cell undergoes ________. G2 phase M phase • Cell division (Mitosis and cytokinesis) Two parts: 1. Nuclear division – _____________________ 2. Cytoplasmic Division – _____________________ MITOSIS • In eukaryotes, it is the main process by which ____________ and tissue ______________ is accomplished. • Mitosis is also the main process by which single-celled and many multi-celled eukaryotes reproduce ______________. Preparation for Mitosis. Organelles are ________________. G1, S, and G2 are known together as ______________________.. Gametes are ______ cells. Somatic cells are “___________” body cells. 4 Steps of Mitosis (PMAT) Prophase: Chromosomes condense and attach to the ____________ fibers at their ________________. Nuclear Membrane breaks down. Centrioles move to opposite sides of the cell and organize the spindle fibers. Metaphase: Chromosomes ________ up in the __________ of the cell. Anaphase: Chromosomes separate-Move to ____________ sides of the cell Telophase: Nuclear Envelope _________ There are now TWO nuclei in one cell! …And they contain the ___________ genetic information *SAME _____________ OF CHROMOSOMES 1 Cell Life Cycle and Reproduction (Mitosis & Meiosis) Name__________________________________________ assign.#_ __ Notes Cytokinesis: • • • • • _________________ division Each cell gets __________ of the organelles. After mitosis: cell _______________ in half to form two new cells. Animal cells pinch. Cytokinesis in plant cells is different from that in animal cells. • In plant cells a _______ _________ forms from the inside out. Results of Mitosis & Cytokinesis • new cells. • The new cells- called daughter cells- have the ________ number of chromosomes as the mother cell. • This occurs in all cells in your body. • You have _______chromosomes in all of your somatic cells-_____ __________! BOOK WORK: on your own 1. 2. Cell Cycle Vocabulary cell division centromere 3. interphase 4. cell cycle 5. mitosis 6. prophase 7. centriole 8. spindle 9. metaphase 10. anaphase 11. telophase 12. cytokinesis 13. cyclin 14. cancer 15. meiosis 16. sister chromatid 2 Cell Life Cycle and Reproduction (Mitosis & Meiosis) Name__________________________________________ assign.#_ __ Mitosis Review 1. The purpose of mitosis is to ensure that: each new cell is genetically different from its parent 6. Most cells spend the majority of their time in: prophase metaphase each new cell receives the proper number of chromosomes interphase gametes are available for reproduction telophase DNA is replicated without errors 2. The image below illustrates what phase of mitosis 7. Cytokinesis begins after which phase? telophase anaphase prophase teleophase anaphase metaphase prophase 3. Which of the following is NOT part of mitosis prophase metaphase telophase interphase 4. Which of the following is the term used for the "connector" between two sister chromatids? metaphase 8. Describe the 2 main purposes of mitosis __________________________________________ __________________________________________ 9. How many times does the cell divide during mitosis? __________________________________________ 10. What kind of cells (somatic or Gametes) are produced at the end of mitosis? __________________________________________ chromosome 11. What are sister chromatids? When are they produced?___________________________________ __________________________________________ chromatid 12. Label the cell to the right: centromere spindle fiber 5. A cell that has 20 chromosomes undergoes mitosis. Which of the following is true? two daughter cells will be created, each have 20 chromosomes two daughter cells will be created, each have 40 chromosomes 4 daughter cells will be created, each having 10 chromosomes 2 daughter cells will be created, each having 10 chromosomes 1) Sister Chromatid 2) Spindle Fibers 3) Centromere 4) Centrol 13) Which phase of mitosis is the cell to the right in? _______________________ 14) If a human skin cell goes through mitosis, how many chromosomes will the two new daughter cells have?____ 15) If an alligator has 12 chromosomes in a somatic cell, how many will it have after a somatic cell undergoes mitosis? ____________ 3 Cell Life Cycle and Reproduction (Mitosis & Meiosis) Name__________________________________________ assign.#_ __ Notes Back to Notes: Reproduction of Sex Cells cells- __________and ________ Process is called ____________ Similar to Mitosis MEIOSIS = CHROMOSOME REDUCTION DIVISION Cell _________ ____________ First division is like mitosis and then the cell divides again to create 4 ________ cells. Diploid In Humans, starts with ___ and ends up with ____. Why? Fertilization creates the _________ condition again Sperm formation- 4 haploid sperm cells are formed. Egg formation-most of the cytoplasm is used in one cell and the other three disintegrate. One haploid egg cell is formed. Crossing Over • Sometime during meiosis the chromosomes can ___________ information • Major source of ___________ ___________ in species. Haploid Prokaryotic Cell Division • __________ _____________ • DNA is ________ and then the cell _________ in half. • ____________ __ Reproduction __________ genetically identical! Contains _____of the genetic information. Regulation of the Cell Cycle • How do cells know when to divide? When to stop dividing? • _______________-___________ that regulate the cell cycle. • Unregulated cell growth can form masses of cells called tumors-___________. • Mitosis and Meiosis Summary Read and answer the questions at the end. Cell division When a cell divides, its two daughter cells must receive the required number of DNA molecules. In eukaryotes, DNA is sorted into two nuclei in the process of mitosis. A separate process divides the cytoplasm in two. Mitosis is the process in which threadlike nuclear material is divided equally between two daughter cells. Mitosis keeps the number of chromosomes constant from one cell generation to the next. In eukaryotes mitotic cell division is the main process by which growth and tissue repair is accomplished. Mitosis is also the main process by which singlecelled and many multi-celled eukaryotes reproduce asexually. Mitosis Mitosis can be broken into four phases: prophase, metaphase, anaphase, and telophase. 4 Cell Life Cycle and Reproduction (Mitosis & Meiosis) Name__________________________________________ assign.#_ __ � During prophase, the duplicated chromosomes become distinct and spindle fibers radiate across the cell. The nuclear envelope starts to break up. � During metaphase, the duplicated chromosomes line up randomly in the center of the cell between the spindles at the spindle equator. � During anaphase, the duplicated chromosomes are pulled to opposite ends of the cell. Every chromosome that was present in the parent cell is now represented by the daughter chromosome at the poles. � During telophase, a nuclear membrane forms around the chromosomes at each end of the cell. The spindle fibers disappear and the chromosomes disperse and become less distinct. Each nucleus has the same chromosome number as the parent cell. The process of mitosis is now complete. Cell division produces two new cells, each with the same number of chromosomes as the original cell. These cells are called diploid cells. In humans, the diploid number is 46. Most of your body cells are produced by cell division and contain 46 chromosomes or 23 pairs of homologous (similar) chromosomes Cytokinesis At the end of telophase, the cytoplasm begins to divide. In animal cells, the plasma membrane forms a groove and “pinches in” at the middle of the cell. This separates the two new nuclei and splits the cell in half. In plant cells, the rigid cell wall prevents a groove from forming. Instead, a cell plate forms along the center of the cell and cuts the cell in half. The cell plate forms new cell walls. Two daughter cells are formed as a result of cytokinesis. They are identical to their parent cell. Cell division allows unicellular organisms to duplicate themselves in a process called asexual reproduction. In multi-cellular organisms, cell division allows them to grow (i.e., increase the size of the organism), develop from a single cell into a multi-cellular organism, and make other cells to repair and replace worn out cells. ****Questions***** 1. In which phase do the chromosomes line up in the middle? 2. When does the cell actually split? 3. What are the two new cells called? 4. Are the two new cells genetically identical or not? 5. Give 2 reasons why a cell might go through mitosis? (I think this would be a great test question. Don’t you?) A few cells are produced differently through a process called meiosis. The cells that are produced as a result of meiosis are called gametes or sex cells. The cell divides two times to form 4 cells. The first meiotic division produces two cells containing half the number of doublestranded chromosomes. The second meiotic division results in the formation of four cells, each containinghalf the number of single-stranded chromosomes. The prefix hap- means “half” so haploid cells contain only one half of each of the pairs of similar chromosomes. In humans, haploid cells contain 23 chromosomes. These cells are called sperm and egg cells. The following are overviews of sperm and egg formation. ♂ During sperm formation, each primary sperm cell develops into four haploid cells of equal size. As they mature, the cells lose most of their cytoplasm and develop a long whip-like tail used in movement. ♀ During egg formation, each primary egg cell that undergoes meiosis develops into one large haploid cell and three smaller haploid cells called polar bodies. The first meiotic division produces one large cell and the first polar body. After the second meiotic division, the large cell forms an egg cell and another polar body. The first polar body may undergo a second meiotic division to produce two more polar bodies. The polar bodies disintegrate. So what is the advantage of uneven cytokinesis? The final egg cell is provided with a larger supply of stored nutrients. ****Question***** 1) How is Meiosis different from Mitosis? 5 Cell Life Cycle and Reproduction (Mitosis & Meiosis) Name__________________________________________ assign.#_ __ Mitosis Lab Name_________________________________________Assign#_______ I. Prepared Slides with microscopes (glass): “Onion Root Tip” Mitosis: Mag: Sketch and label at least 2 different cells undergoing Mitosis. ***Give the name of the phase the cells are in. Animal Cell “Fish Blastula” Mitosis: Sketch and label at least 2 different cells undergoing Mitosis. ***Give the name of the phase the cells are in. Mag: Animal Cell “Uterus” Mitosis: Mag: Sketch and label at least 2 different cells undergoing Mitosis. II. Microslide Viewers: “Animal Mitosis” a) Slide #2: Sketch and label the chromosomes. Phase:__________ b) Slide #3: Sketch and label the chromosomes. Phase:__________ Mag: Mag: c) Slide #6: Sketch and label the chromosomes. Phase:__________ Mag: Phase:__________ Mag: d) Slide #7: Sketch and label the chromosomes. 6 Cell Life Cycle and Reproduction (Mitosis & Meiosis) Name__________________________________________ assign.#_ __ Post lab questions: 1. Fill in the vinn diagram by comparing and contrasting mitosis and Meiosis: 2. Discuss the reasons why cells go through Mitosis? 3. Discuss the reasons why cells go through Meiosis? 4. What molecules regulate the cell cycle? What happens when the cell cycle is uncontrolled? 5. What is nondisjunction? When does it happen? What does it cause? Cell Cycle Online 1) Why must a cell divide? a) Why must cells divide? Click next and watch the cell. 2) Cell Cycle Video a) What are the 4 parts of the cycle? Label the circle b) What happens during each (be brief)? Add this to the circle. c) What controls the cell cycle? What molecules? d) What can happen if the cell cycled is uncontrolled? 3) Mitosis video Clip a) In mitosis a cell reproduces by ____________ into ____ genetically ___________________ cells. b) Make a sketch of a cell from each phase. Give the name of the phase: _______________ ________________ ________________ _______________ c) Are the cells genetically identical after the split? __________ 7 Cell Life Cycle and Reproduction (Mitosis & Meiosis) Name__________________________________________ assign.#_ __ 4) Biology in Motion Mitosis a) Click “practice mitosis.” Make the cell go through mitosis. Draw the final 2 cells . Meiosis b) Click “practice meiosis.” Make the cell go through meiosis. Draw the final 4 cells . c) How are mitosis and meiosis different? 5) Meiosis Video a) Meiosis is the process by which a ______ nucleus divides ____ to produce ____ __________ nuclei. b) What are the products of meiosis in animals? c) When homologous chromosomes exchange pieces of DNA the process is called ____________________. d) How is meiosis different from mitosis? _________________________________________________________ _______________________________________________________________________________________ e) What is the end result of meiosis? _____________________________________________________________ 6) Mitosis vs. Meiosis Click through the animation and just watch the cells divide. (You only need to look at the pictures) 1) How are the two processes similar? 2) How are the two processes different? 7) Try the practice quizzes and see how you do 8) Post activity questions: 1. What is the cell cycle? 2. What is mitosis? 3. What kinds of cells go through mitosis? 4. Why do cells go through mitosis? 5. Are the cells diploid or haploid at the beginning of mitosis? At the end? 6. Are the daughter cells genetically identical after mitosis? 7. What is meiosis? 8. What kinds of cells go through meiosis? 9. Why do cells go through meiosis? Mitosis Meiosis 10. Are the cells diploid or haploid at the beginning of meiosis? At the end? 11. Are the daughter cells genetically identical after meiosis? 8