Regulation of the Cell Cycle

Asexual Reproduction

Cancer

Unit 5b

Cell division in our life cycle.

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Telomeres

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Cell CycleM

(mitosis)

G1(Gap 1)

G2(Gap 2)

S(DNA

Synthesis)

Cells that cease

division

a protective section of DNA at the end of each chromosome.

get shorter every time the cell divides.

Cyclin

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Telomeres

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Regulation of the Cell CycleCdk 

MPF P53 

P27 

When the telomere becomes too short, the cell dies.

Cells that rebuild the telomere with each division can become cancerous

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Some chromosomes are circular, others are linear.

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genetic information is carried in a single, circular chromosome.

DNA is attached at one site to the cell membrane.

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Prokaryotes

much more DNA than Prokaryotes.

genetic information is organized into linear chromosomes.

float freely in the nucleus.

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Eukaryotes

Asexual Reproduction

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One parent

Same genetic blueprint as the parent (clone)

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Asexual Reproduction

Binary Fission Budding Parthenogenesis Regeneration Rhizomes Spore Formation Cloning

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Asexual Reproduction

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Advantages and Disadvantages of Asexual Reproduction

Asexual Reproduction in Organisms

Dolly the Cloned Sheep

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How might telomere length be affected in a cloned animal like “Dolly” the sheep?

1. Telomeres might be longer than normal.

2. Telomeres might be shorter than normal.

3. Telomeres might be of normal length.

4. No telomeres would be present.

Binary fission - Bacteria. The circular chromosome duplicates itself and the cell splits into two identical new cells.

Budding - grow directly on the body of the parent. It eventually breaks off and establishes itself as a new, separate organism.

Regeneration - part of the parent's body breaks off and grows into a complete, new organism.

Rhizomes - Some plants (strawberries, potatoes, certain types of grass, etc) form runners that spread out from the parent plant to form plantlets at their ends.

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Asexual Reproduction

Spore formation - fungi and some algae develop into a new organism after dispersal. 

Parthenogenesis - the development of an egg that has not been fertilized into an individual. Animals like most kinds of wasps, bees, and ants that have no sex

asexual reproduction are genetically identical copies, or clones, of the parent.

Cloning of mammals

Dolly the sheep

Cloning

Cell division out of control means cancer.

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Cancer

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“Cancer cells are those which have forgotten

how to die.”—Harold Pinter

Cancer unrestrained cell growth and division

can lead to tumors

second leading cause of death in the United States

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Tumor Growth unregulated cell division

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Cancer cells have several features that distinguish them from normal cells, including…

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Benign and Malignant Tumors

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What is cancer?

Contact Inhibition

How does it cause death?

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Why is the treatment for cancer often considered as bad as the disease?

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Chemotherapy and radiation affect cancer cells and normal cellsBoth treatments affect cells that are actively dividing.

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CancerUnrestrained cell growth and division.

Large masses of cells called malignant tumors that can cause serious health problems.

Treatment focuses on killing or slowing the division of the cells using chemotherapy and/or radiation.

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