Sexual v. Asexual Reproduction

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Sexual v. Asexual Reproduction
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Binary Fission
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Chromosome Structure

• Eukaryotic chromosomes contain DNA and protein
  tightly packed together to from chromatin.
• Chromatin consists of DNA tightly coiled around
  proteins called histones.
• DNA histone molecules form nucleosomes, which
  pack together to form thick fibers of
  chromosomes.

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The Cell Cycle
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Mitosis
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Whitefish Blastula
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Mitosis in Plant Cells
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Onion Root Tip
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Controls on the Cell Cycle

• Some cells stop dividing when mature (stay in G0)
• ex) many neurons (nerve) muscle cells
• Others divide for growth repair
• Influences of cell division
• Growth factors protein that stimulates cell
  division
• Density-dependent inhibition (cell to cell
  contact)
• Anchorage dependent

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Cell Cycle Regulators

• Proteins called cyclins start/stop the cell
  cycle.
• The cycle is regulate by various factors
• Intracellular factors
• All chromosomes are replicated
• All spindles are attached
• Extra-cellular factors
• Binding of growth factors
• Cell to cell contact

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Growing Out of Control Cancer

• Cancer is a disease of the cell cycle
• Cells do not respond normally to controls of the
  cell cycle system
• Tumor abnormally growing mass of body cells
• Benign abnormal cells remain at original sight
  forming a lump although can cause problems,
  normally can be fully removed by surgery
• Malignant spread, displacing normal tissue and
  disrupting organ function
• Metastasis spread of cancer cells via
  circulatory system transport

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Molecular Basis of Cancer

• Tumor Suppressor Genes (p53)
• - genes that normally halt the cell cycle
• - problem if stuck OFF (cells keep
  dividing)
• Oncogenes
• - genes that tell cells to divide
• - problem if stuck ON (cells keep dividing)

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Cancer categorized based on site of origin

• Carcinoma originate in internal or external
  coverings of the body (skin or lining of
  intestine)
• Sarcoma Arise in support tissue (bone or muscle)
• Leukemia Arise in blood or bone marrow
  (abnormal number of white blood cells)
• Lymphoma Arise in lymphatic cells of the immune
  system (lymph nodes or spleen)

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Treating Cancer

• Localization and surgical removal of tumor
• Radiation
• Damages DNA in cancer cells more than normal cell
• Cancer cells do not have the ability to repair
• Cancer cells die without dividing/reproducing
• Chemotherapy (For widespread or metastatic
  tumors)
• Chemicals that disrupt specific steps in the cell
  cycle
• freezes the mitotic spindle
• prevents formation of spindle
• Damage DNA or RNA involved in making growth
  factors