1. How Cells Divide MITOSIS
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2. Cell Division in Prokaryotes
Prokaryotic cell division occurs as binary fission in which the cell divides into two halves.
Genetic information exists as a single, circular double-stranded DNA molecule
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3. Discovery of Chromosomes
All eukaryotic cells store genetic information in chromosomes.
Most eukaryotes have between 10 and 50 chromosomes in their body cells.
Human cells have 46 (23 pairs).
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4. Structure of Chromosomes
Chromosomes are composed of chromatin, a complex of DNA and protein.
Karyotype - An individual’s particular array of chromosomes.
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5. Structure of Chromosomes
Diploid - A cell possessing two copies of each chromosome (Human body cells, somatic cells).
Homologous chromosomes contain the same type of information
Haploid - A cell possessing a single copy of each chromosome (reproductive cells or gametes).
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6. Mitosis-getting ready for cell division
Interphase
Most of the life of a cell is spent in interphase
Growth
Development
DNA replicates
Nucleus visible-chromatin is loose within the nuclear envelope
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7. Mitosis Prophase: *Spindle apparatus assembled.
*DNA coils tightly, chromosomes are visible
*Nuclear envelope breaks.
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9. Chromosomes align in cell’s center (“equator”)
Mitosis
Metaphase
Chromosomes align in cell’s center (“equator”)
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10. Mitosis Anaphase Sister chromatids pulled towards poles.
Poles move apart.
Centromeres move toward poles.
Microtubules shorten.
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11. Mitosis Telophase Spindle disassembles.
Nuclear envelope forms around each set of sister chromatids.
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12. Identify each phase in the illustration below
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13. A. production of reproductive cells B. preparation for cell division
What is Mitosis?
A. production of reproductive cells
B. preparation for cell division
C. reducing the genetic material
D. making DNA
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14. B. repairing tissues of an organism C. production of eggs or sperm
All of the following are reasons for cell division following mitosis except which one?
A. growth of an organism
B. repairing tissues of an organism
C. production of eggs or sperm
D. replacing dead or worn out cells
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15. Place the following phases in the correct order: interphase, prophase, metaphase, anaphase, telophase
C. 1, 3, 2, 4, 5
D. 4, 5, 3, 2, 1
A. 1, 2, 3, 4, 5
B. 5, 4, 2, 3, 1 2 5 1 3 4
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16. Cytokinesis Cleavage of cell into two halves. Animal Cells
Constriction belt of actin filaments.
Plant Cells
Cell plate forms
Fungi and Protists
Mitosis occurs within the nucleus.
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17. Cancer and Cell Proliferation
Cancer is essentially a failure of cell division control.
A certain gene controls cell division.
Halts cell division if it detects damaged DNA and stimulates activity of repair enzymes.
Appears to be absent in many cancerous cells.
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18. Copyright © McGraw-Hill Companies Permission required for reproduction or display
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