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Chapter 9 Cellular Reproduction
Section 1: Cellular Growth Section 2: Mitosis and Cytokinesis Section 3: Cell Cycle Regulation
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9.1 Cellular Growth Objectives:
Explain why cells are relatively small. Summarize the primary stages of the cell cycle. Describe the stages of interphase.
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9.1 Cellular Growth Main Idea – Cells grow until they reach their size limit, then they either stop growing or divide.
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1. Most cells are smaller than the period at the end of this sentence.
2. The key factor that limits the size of a cell is the ratio of its surface area to its volume.
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3. The surface area of the cell is the area covered by the plasma membrane. To calculate the surface area of the cube multiply L x W x number of sides (6)
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4. The volume refers to the space taken up by the contents of the cell
4. The volume refers to the space taken up by the contents of the cell. To calculate the volume, multiply L x W X H 5. As a cell grows, it’s volume increases more rapidly than the surface area. As a cell increases in size the surface area to volume decreases
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Ratio of Surface Area to Volume
Chapter 9 Cellular Reproduction 9.1 Cellular Growth Ratio of Surface Area to Volume
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If a cell is too large it may have difficulty supplying nutrients and expelling waste products.
Cells remain small to maximize the ability of diffusion and motor proteins to transport nutrients and waste products.
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Small cells maintain more efficient transport systems.
The need for signaling proteins to move throughout the cell also limits cell size. Cell size affects the ability of the cell to communicate instructions for cellular functions.
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Cells reproduce by a cycle of growing and dividing.
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In the cell cycle, a cell stays in Interphase the longest 12.There are three main stages of the cell cycle interphase, mitosis, and cytokinesis.
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Diagram of cell cycle – see pg. 246
Interphase Longest phase Cell grows DNA replication occurs Mitosis Nucleus divides Occurs in 4 stages Cytokinesis Shortest phase Cytoplasm divides
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Chapter 9 Cellular Reproduction 9.1 Cellular Growth Interphase is the stage during which the cell grows, carries out cellular functions, and replicates. Mitosis is the stage of the cell cycle during which the cell’s nucleus and nuclear material divide. Cytokinesis is the method by which a cell’s cytoplasm divides, creating a new cell.
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13. The duration of the cell cycle varies, depending on the cell that is dividing.
For most normal, actively dividing animal cells, the cell cycle takes approximately 12-24 hours.
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15. During interphase, the cell grows, develops into a functioning cell, duplicates it’s DNA, and prepares for division.
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16.Interphase is divided into 3 stages G1,
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17. Chromosomes – contain genetic material
17. Chromosomes – contain genetic material. Chromatin – relaxed form of DNA in nucleus copies it’s DNA in preparation for cell division.
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18. In mitosis, the cell’s nuclear material divides and separates into opposite ends of the cell. 19. In cytokinesis, the cell divides into 2 daughter cells, with identical nuclei.
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20. The cell cycle is the method by which eukaryotic cells reproduce themselves. 21. Prokaryotic cells, reproduce by a method called binary fission.
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9.2 Mitosis and Cytokinesis
Objectives: Describe the events of each stage of mitosis. Explain the process of cytokinesis. Main Idea Eukaryotic cells reproduce by mitosis, the process of nuclear division, and cytokinesis, the process of cytoplasm division.
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Mitosis The key activity of mitosis is the accurate separation of the cell’s replicated DNA. The process of mitosis increases the number of cells as a young organism grows to its adult size. Organisms also use mitosis to replace damaged cells.
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The Stages of Mitosis 4. The 4 stages of mitosis are: prophase, metaphase, anaphase and telophase.
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Prophase- the first stage of mitosis—cell spends most of its time here
Chapter 9 Cellular Reproduction 9.2 Mitosis and Cytokinesis The Stages of Mitosis Prophase- the first stage of mitosis—cell spends most of its time here
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5. Chromatin tightens or condenses into chromosomes
5. Chromatin tightens or condenses into chromosomes. This action facilitates chromosome movement. 6. As prophase continues, the nucleolus seems to disappear.
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7. Microtubule structures called spindle fibers form in the cytoplasm
7. Microtubule structures called spindle fibers form in the cytoplasm. 8. Near the end of prophase, the nuclear envelope disappears.
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Chapter 9 Cellular Reproduction 9.2 Mitosis and Cytokinesis Metaphase 9. Sister chromatids are pulled by motor proteins along the spindle apparatus toward the center of the cell and line up in the middle, or equator of the cell.
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10. The chromatids are pulled apart.
Chapter 9 Cellular Reproduction 9.2 Mitosis and Cytokinesis Anaphase 10. The chromatids are pulled apart. 11. At the end of anaphase, the microtubules, with the help of motor proteins, move the chromatids toward the poles of the cell.
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13. Two new nuclear membranes begin to form and the nucleoli reappear.
Chapter 9 Cellular Reproduction 9.2 Mitosis and Cytokinesis Telophase 12. Chromosomes arrive at the poles of the cell and begin to relax or decondense. 13. Two new nuclear membranes begin to form and the nucleoli reappear.
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Cytokinesis – process that divides the cytoplasm
14. This results is 2 cells, each with identical nuclei.
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15. In animal cells, cytokinesis is accomplished by using microfilaments to constrict or pinch the cytoplasm.
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16. In plant cells, a new structure called a cell plate forms between two daughter cells. Cell walls then form on either side of the cell plate.
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The 4 Stages of Mitosis http://www.johnkyrk.com/mitosis.html
Prophase – “poles form” (centrioles) chromosomes condense; spindle forms Metaphase – “meet in the middle” chromosomes line up at the equator Anaphase – “pull apart” chromosomes move to opposite poles Telophase – “pinch together” nuclear envelope forms; chromosomes decondense
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Remember the Stages of Cell Division
I Interphase Probably Prophase Make Metaphase A Anaphase Teacher Telophase Crazy Cytokinesis
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Prokaryotic cells undergo binary fission- cell divides into 2 genetically identical cells
WHY? Prokaryotic cells do not have a nucleus. Mitosis is division of the nucleus.
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Binary Fission - lhs.lps.org
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2. Mitosis Prophase Nuclear membrane disintegrates;
chromosomes condense Metaphase Chromosomes attach to spindle and line up at the equator of cell Anaphase Chromosomes move apart to opposite poles Telophase Cell pinches together; Chromosomes relax
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9.3 Cell Cycle Regulation Objectives:
Summarize the role of cyclin proteins in controlling the cell cycle. Explain how cancer relates to the cell cycle. Describe the role of apoptosis. Summarize the two types of stem cells and their potential uses. Main Idea - The normal cell cycle is regulated by cyclin proteins.
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CELL DIVISION GENES The rate of cell division varies depending on the type of cell. Some cells divide frequently (some human skin cells divide once/hour) Some cells divide occasionally (liver cells divide about once/year) Some cells don’t divide once they form (nerve cells)
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A mechanism involving proteins and enzymes control the cell cycle.
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2. These proteins are called cyclins because they regulate the timing of the cell cycle in eukaryotic cells.
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3. Cyclins bind to enzymes called cyclin-dependent kinases(CDKs) to start various activities that take place in the cell cycle.
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4. Cyclin/CDK combinations occur only during the stages of interphase and mitosis.
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5. Different cyclins/CDK’s combinations control different activities at different stages in the cell cycle.
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6. The different cyclin/CDK combinations signal the start of the cell cycle, DNA replication, protein synthesis, nuclear division and the end of the cell cycle.
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7. The cell cycle also has built in checkpoints that monitor the cycle and can stop it if something goes wrong.
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Cell Cycle with checkpoints
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Chapter 9 Cellular Reproduction Checkpoints occur at the end of G1, during the S stage, in the G2 stage and at beginning of mitosis.
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Chapter 9 Cellular Reproduction 9.3 Cell Cycle Regulation 9. When cells don’t respond to the normal cell cycle control mechanisms, a condition called cancer can result.
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10. Cancer is the uncontrolled growth and division of cells--a failure in the regulation of the cell cycle.
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NO CONTACT INHIBITION Cancer cells don’t stop when they touch nearby
they just keep growing! That’s what makes a tumor.
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Control of Cell Division
Section 10-3 If center cells are removed, cells near the space will start to grow again. SHOWS: Cell division genes can be turned on and off Cells grow until they touch other cells Contact Inhibition
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11. When unchecked, cancer cells can kill an
11. When unchecked, cancer cells can kill an organism by crowding out normal cells, resulting in the loss of tissue function.
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Comparison of Normal and Cancerous Stomach Cells
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12. Cancer cells spend less time in interphase than do
12. Cancer cells spend less time in interphase than do normal cells, which means cancer cells grow and divide unrestrained as long as they are supplied with essential nutrients.
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Cancerous Stomach Cells
Normal Stomach Cells Interphase 120 min. Prophase min. Metaphase min. Anaphase min. Telophase min. Cancerous Stomach Cells Interphase 16 min. Prophase 15 min. Metaphase 2 min. Anaphase 1 min. Telophase 3 min.
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Cancer cells Don’t stop dividing Like a “car with no brakes”
Can spread to new places (METASTASIS)
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A. Causes of Cancer 13. The changes that occur in the regulation of cell growth and division of cancer cells are due to mutation or changes in the segments of DNA that control the production of proteins.
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14. Mutations are permanent changes in a
14. Mutations are permanent changes in a cell’s DNA; can cause changes in the growth of a cell leading to cancer.
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15. Various environmental factors can affect the occurrence of cancer cells. 16. Substances and agents that are known to cause cancer are called carcinogens. Examples: Ultraviolet light, cigarette smoke, tobacco, x-rays, asbestos, some pesticides, arsenic, some viruses, etc.
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B. Cancer genetics 17. More than one change in DNA is required to change an abnormal cell into a cancer cell.
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18. The risk of cancer increases with age
18. The risk of cancer increases with age. Because, number of mutations increases with age. 19. The fact that multiple changes must occur also might explain why cancer runs in some families
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20. When an embryo divides, some cells go
20. When an embryo divides, some cells go through a process called apoptosis, or programmed cell death.
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21. Examples of apoptosis occur during
21. Examples of apoptosis occur during the development of human hand and foot; in plants, leaves falling from trees during autumn. 22. Apoptosis also occurs in cells that are damaged beyond repair including cells with DNA damage that could lead to cancer.
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Stem cells – 23. The majority of cells in a multicellular organisms are designed for a specialized function. 24. Stem cells are unspecialized cells that can develop into specialized cells; 2 types Adult stem cells and Embryonic stem cells
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Possible uses for stem cells
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Embryonic stem cells 25. An embryo results from the fertilization of an egg by a sperm. These unspecialized cells are embryonic stem cells.
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26. Embryonic stem cells research is controversial because of ethical concerns about the source of the cells. 27. Ethics are values in society that consider the rightness or wrongness of certain actions
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Adult stem cells 28. Adult stem cells are found in various tissues in the body and might be used to maintain and repair the same kind of tissue in which they are found. 29. Research with adult stem cells is much less controversial because the adult stem cells can be obtained with the consent of their donor.
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9.3 Section Assessment pg. 257 (1-7)
Certain cyclin proteins and cyclin-dependent enzymes regulate mitosis and the cell cycle. The cancer cell cycle is shorter. Cancer cells divide in an uncontrolled way. Three carcinogens are cigarette smoke, UV radiation, and asbestos.
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In apoptosis a cell undergoes programmed cell death; cancer cells divide unrestrained as long as they are supplied with essential nutrients. Stem cells may be used to treat medical conditions and genetic defects.
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Embryonic stem cells, found in developing embryos, can develop into many kinds of cells. Adult stem cells are found in developed tissues and might be used to maintain and repair the same kind of tissue in which they are found.
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If apoptosis did not occur to cells with significant DNA damage people would probably have higher rates of cancer and genetic diseases.
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Chapter Resource Menu Chapter Diagnostic Questions
Cellular Reproduction Chapter Resource Menu Chapter Diagnostic Questions Formative Test Questions Chapter Assessment Questions Standardized Test Practice biologygmh.com Glencoe Biology Transparencies Image Bank Vocabulary Animation Click on a hyperlink to view the corresponding lesson.
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1. Which is the first phase of mitosis?
Chapter 9 Cellular Reproduction Chapter Diagnostic Questions 1. Which is the first phase of mitosis? interphase prophase metaphase telophase
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During what phase do the sister
Chapter 9 Cellular Reproduction Chapter Diagnostic Questions During what phase do the sister chromatids line up in the middle of the cell? interphase metaphase anaphase telophase
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3. Which is not a phase of the cell cycle?
Chapter 9 Cellular Reproduction Chapter Diagnostic Questions 3. Which is not a phase of the cell cycle? cytokinesis interphase apoptosis mitosis
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1. Which can more efficiently supply nutrients and
Chapter 9 Cellular Reproduction 9.1 Formative Questions 1. Which can more efficiently supply nutrients and expel waste products? larger cells smaller cells cells with lower surface area to volume ratio cells shaped like a cube
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2. At what stage does a cell spend most of its life?
Chapter 9 Cellular Reproduction 9.1 Formative Questions 2. At what stage does a cell spend most of its life? cytokinesis interphase mitosis synthesis
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3. What happens in the cell during cytokinesis?
Chapter 9 Cellular Reproduction 9.1 Formative Questions 3. What happens in the cell during cytokinesis? The cell grows and carries out normal functions. The cell copies its DNA and forms chromosomes. The cell’s nucleus and nuclear material divide. The cell’s cytoplasm divides.
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4. In what stage of the cell cycle does the
Chapter 9 Cellular Reproduction 9.2 Formative Questions 4. In what stage of the cell cycle does the cell’s replicated genetic material separate? cytokinesis interphase mitosis prophase
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5. Which diagram shows anaphase?
Chapter 9 Cellular Reproduction 9.2 Formative Questions 5. Which diagram shows anaphase?
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At the end of mitosis the nuclear material is
Chapter 9 Cellular Reproduction 9.2 Formative Questions 6. True or False At the end of mitosis the nuclear material is divided and two new cells have formed.
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What are the “key and ignition” that start
Chapter 9 Cellular Reproduction 9.3 Formative Questions What are the “key and ignition” that start the various activities in the cell cycle? chromatin and chromosomes cyclin and CDKs microtubules and spindle fibers protein and ribosomes
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8. Which of these cancer-causing substances
Chapter 9 Cellular Reproduction 9.3 Formative Questions 8. Which of these cancer-causing substances or agents is impossible to avoid completely? chemicals such as asbestos food and drinks that the FDA warns may contain carcinogens tobacco and second-hand smoke ultraviolet radiation from the Sun
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What is the term for the programmed
Chapter 9 Cellular Reproduction 9.3 Formative Questions What is the term for the programmed death of cells that are damaged beyond repair or have harmful changes in their DNA? apoptosis carcinogens cytokinesis mitosis
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Which cells are not locked into becoming
Chapter 9 Cellular Reproduction 9.3 Formative Questions Which cells are not locked into becoming one particular kind of cell and are capable of developing into specialized tissues? apoptotic cells cancer cells prokaryotic cells stem cells
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11. This cell has completed what stage of mitosis?
Chapter 9 Cellular Reproduction Chapter Assessment Questions 11. This cell has completed what stage of mitosis? anaphase interphase metaphase telophase
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What term is used to describe programmed cell death?
Chapter 9 Cellular Reproduction Chapter Assessment Questions What term is used to describe programmed cell death? apoptosis anaphase necrosis cyclins
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13. What is the role of cyclins in a cell?
Chapter 9 Cellular Reproduction Chapter Assessment Questions 13. What is the role of cyclins in a cell? to control the movement of microtubules to signal for the cell to divide to stimulate the breakdown of the nuclear membrane to cause the nucleolus to disappear
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C B A 14. Which cell has the lowest ratio of surface area to volume?
Chapter 9 Cellular Reproduction Standardized Test Practice 14. Which cell has the lowest ratio of surface area to volume? C B A
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15. At what stage of interphase does the cell take
Chapter 9 Cellular Reproduction Standardized Test Practice 15. At what stage of interphase does the cell take inventory and make sure it is ready for the division of its nucleus? G1 S G2 M
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Which occurs in plant cells but not animal
Chapter 9 Cellular Reproduction Standardized Test Practice Which occurs in plant cells but not animal cells during the cell cycle? formation of a cell plate formation of microtubules formation of a cleavage furrow at the equator of the cell movement of chromosomes to the poles of the cell
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17. Multiple changes in DNA are required to
Chapter 9 Cellular Reproduction Standardized Test Practice True or False 17. Multiple changes in DNA are required to change an abnormal cell into a cancer cell.
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18. Which is not a condition that can result in cancer?
Chapter 9 Cellular Reproduction Standardized Test Practice 18. Which is not a condition that can result in cancer? a failure in the control mechanisms that regulate the cell cycle a failure in the repair systems that fix changes or damage to DNA a failure of the spindle fibers to move chromosomes during mitosis mutations or changes in segments of DNA that control protein production
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Glencoe Biology Transparencies
Chapter 9 Cellular Reproduction Glencoe Biology Transparencies
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Chapter 9 Cellular Reproduction Image Bank
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Section 1 Vocabulary cell cycle interphase mitosis cytokinesis
Chapter 9 Cellular Reproduction Vocabulary Section 1 cell cycle interphase mitosis cytokinesis chromosome chromatin
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Section 2 Vocabulary prophase sister chromatid centromere
Chapter 9 Cellular Reproduction Vocabulary Section 2 prophase sister chromatid centromere spindle apparatus metaphase anaphase telophase
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Section 3 Vocabulary cyclin cyclin-dependent kinase cancer carcinogen
Chapter 9 Cellular Reproduction Vocabulary Section 3 cyclin cyclin-dependent kinase cancer carcinogen apoptosis stem cell
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Visualizing the Cell Cycle
Chapter 9 Cellular Reproduction Animation Visualizing the Cell Cycle
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