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The Cellular Basis of Inheritance
Chapter 9 p.179
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All cells come from cells (9.1)
Objectives Describe how cell reproduction contributes to repair and to growth. Contrast the two main ways that organisms reproduce. Key Terms asexual reproduction sexual reproduction
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Repair and Growth -The skin on your arm.
Figure 9-1 Cell reproduction enables your body to produce new skin cells that replace dead cells at your skin's surface. 3 3
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Reproduction -e.g Paramecium, geranium
-Asexual reproduction: process in which a single cell or set of cells produces offspring that inherit all their genetic material from one parent -e.g Paramecium, geranium 4 4
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Reproduction -e.g Birds, human.
-Sexual reproduction: process in which genetic material from two parents combines and produces offspring that differ genetically from either parent. -e.g Birds, human. 5 5
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1. Relate cell reproduction to the replacement of skin cells.
Concept Check 9.1 1. Relate cell reproduction to the replacement of skin cells. 2. Describe two ways in which asexual and sexual reproduction differ. 3. How is cell division involved in growth? 6 6
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The cell cycle multiplies cells (9.2)
Objectives Describe the structure of a chromosome. Name the stages of the cell cycle and explain what happens during each stage. Key Terms chromatin chromosome sister chromatid centromere cell cycle interphase mitotic phase mitosis cytokinesis
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Chromosomes and Cell Division
-200 trillion cells. chromatin chromosome sister chromatid centromere Figure 9-4 Each chromosome in a reproducing cell undergoes the duplication and separation process shown here. Duplication occurs during interphase, in preparation for cell division. 8 8
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The Cell Cycle -Interphase 9
Figure 9-5 In humans and other mammals, cells that reproduce daily have a cell cycle that usually lasts 10 to 20 hours. The S phase takes about 3 to 6 hours, while the G2 phase is slightly shorter. 9 9
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The Cell Cycle -Mitotic Phase mitosis cytokinesis 10
Figure 9-6 This diagram of the cell cycle, showing only one chromosome, highlights the mitotic phase (M). The duplicated chromosomes are separated during mitosis and distributed into daughter cells that form through cytokinesis. (The term "daughter" refers to offspring cells and does not imply female gender.) 10 10
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3. Summarize the events that occur during mitosis and cytokinesis.
Concept Check 9.2 1. Describe how the appearance of chromosomes changes as a cell is about to divide. 2. Interphase used to be described as a "resting phase." Why is this description inaccurate? 3. Summarize the events that occur during mitosis and cytokinesis. 11 11
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The Cell Cycle Which of the following is a correct statement about the events of the cell cycle? a. Little happens during the G1 and G2 phases. b. DNA replicates during cytokinesis. c. The M phase is usually the longest phase. d. Interphase consists of the G1, S, and, G2 phases. 12 12
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Cells divide during the mitotic phase (9.3)
Objectives Summarize the major events that occur during each phase of mitosis. Explain how cytokinesis differs in plant and animal cells. Key Terms spindle centrosome prophase metaphase anaphase telophase cell plate
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The Mitosis Dance Spindle: Centrosomes: Centrioles: 14
Figure 9-8 Mitosis begins after the chromosomes have duplicated in interphase and ends when telophase is completed. 14 14
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The Mitosis Dance Figure 9-8 Mitosis begins after the chromosomes have duplicated in interphase and ends when telophase is completed. 15 15
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The Mitosis Dance Interphase: Prophase : Metaphase: Anaphase: Telophase: and Cytokenesis: Figure 9-8 Mitosis begins after the chromosomes have duplicated in interphase and ends when telophase is completed. 16 16
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Cytokinesis in Animals and Plants
cell plate: Figure 9-9 In a dividing plant cell the growing cell plate eventually fuses with the plasma membrane of the parent cell, and the cell wall material joins the existing cell wall. Two daughter cells result, each with its own plasma membrane and cell wall. 17 17
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2. Compare and contrast cytokinesis in animal and plant cells.
Concept Check 9.3 1. Describe a significant event that occurs in each of the four stages of mitosis. 2. Compare and contrast cytokinesis in animal and plant cells. 3. In what sense may prophase and telophase in mitosis be characterized as opposites? 18 18
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Copyright Pearson Prentice Hall
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Mitosis Overview http://www. 5min
Copyright Pearson Prentice Hall
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Cancer cells grow and divide out of control (9.4)
Objectives Compare benign and malignant tumors. Explain how cancer treatments can work at the cellular level. Key Terms benign tumor malignant tumor cancer metastasis
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Tumors and Cancer what is cancer? benign tumor: mass of normal cells that remain at their original site malignant tumor: mass of abnormal cells resulting from uncontrolled cancer cell division cancer: disease caused by severe disruption of the mechanisms that normally control the cell cycle metastasis: spread of cancer cells beyond their original site in the body 22 22
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Tumors and Cancer Figure 9-11 Cells in a cancerous tumor reproduce at an abnormally fast rate and become irregular in appearance. When individual cells metastasize (travel from the original tumor), the cancer can spread. 23 23
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Cancer Treatment 24 24
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1. List two differences between benign tumors and malignant tumors.
Concept Check 9.4 1. List two differences between benign tumors and malignant tumors. 2. How might drugs that interfere with mitosis be effective in treating cancer? 3. How is cancer related to cell reproduction? 25 25
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Meiosis functions in sexual reproduction (9.5)
Objectives Describe how homologous chromosomes are alike and how they differ. Contrast haploid and diploid cells. Summarize the process of meiosis. Key Terms meiosis karyotype homologous chromosome sex chromosome diploid gamete haploid fertilization zygote tetrad 26 26
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Homologous Chromosomes
Meiosis: type of cell division that produces four cells, each with half as many chromosomes as the parent cell Karyotype: display of a person's 46 chromosomes Homologous chromosome: one of a matching pair of chromosomes, one inherited from each parent Figure 9-13 Karyotype displays are made when chromosomes are visible during metaphase; therefore, each chromosome actually consists of two chromatids. In a true karyotype you would not be able to distinguish the sister chromatids. This illustration, however, shows how a homologous pair would look if you could distinguish the sister chromatids on each chromosome. 27 27
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Homologous Chromosomes
Meiosis: type of cell division that produces four cells, each with half as many chromosomes as the parent cell Karyotype: display of a person's 46 chromosomes Homologous chromosome: one of a matching pair of chromosomes, one inherited from each parent Sex chromosome: one of two chromosomes of the 23rd pair of human chromosomes, which determine an individual's gender Figure 9-13 Karyotype displays are made when chromosomes are visible during metaphase; therefore, each chromosome actually consists of two chromatids. In a true karyotype you would not be able to distinguish the sister chromatids. This illustration, however, shows how a homologous pair would look if you could distinguish the sister chromatids on each chromosome. 28 28
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