bio aging final exam Systemic Theories.txt

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bio aging final exam Systemic Theories.txt
2012-12-12 14:59:03
bio aging final exam Systemic Theories

bio aging final exam Systemic Theories
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  1. Systemic mechanism
    • Involves complex regulatory mechanisms
    • STRENGTH: CAN Account for differences among DIFFERENT species
    • WEAKNESS: Difficulty accounting for varied mortality rates of SAME species
    • 2 main Systemic theories include METABOLIC and GENETIC
  2. Metabolic Theory
    • Systemic and INTRACELLULAR
    • one of 2 main systemic theory
    • Include 2 subtheories: 1. Rate-of-living Theory and 2. Mitochondrial damage Theory
    • longevity INVERSELY related to metabolic rate
  3. Rate-of-living theory
    • one of the Metabolic theories
    • First suggested by Max Rubner & Pearl: showed metabolic rates correlated with longevity
    • Newer evidence now contradicts Pearls' rate-of-living theory
    • evidence from exercised vs. non-exercised animals (do not show any difference in MAXIMUM lifespan)
    • oxygen consumption rates similar for all types of Dros, even if they have different lifespans
  4. Mitochondrial Damage theory
    • one of the Metabolic Theories
    • First suggested by Jaime Miguel: showed Vitamin E, which positive correlation with longevity in Dros., is in HIGH concentration in INNER-Mitochondrial Membrane
    • Suggested Vit. E was protecting mitochondria from age-related damage
    • Recent hypotheses from Wallace look at mitochondrial DNA as most likely Functional Target of Age-related damage
  5. Mitochondrial DNA as target of Age-related damage hypotheses
    • 1. Rates of free radical damage to mitochondrial DNA are 10x GREATER vs. rates of damage to nuclear DNA
    • 2. DNA repair rates in Mitochondria are SLOWER and LESS Accurate vs. nuclear DNA
    • 3. Mitochondrial DNA deletions found to be associated with human pathologies, suggesting age-related deletions may have fxnal consequences.
    • 4. Rates of unrepaired MITOCHONDRIAL DNA damage MORE correlated with SPECIES-specific lifespans vs. rates of unrepaired NUCLEAR DNA damage
  6. Genetic Theories
    • Systemic and INTRACELLULAR
    • one of 2 main systemic theory
    • longevity from Particular set of genes
  7. Types of Genetic theories
    • 1. Antioxidant defense enzymes
    • 2. Energy, Stress and long life: antioxidant activity shown to correlate with low mortality rates in response to stressors such as toxicity, heat shock and desiccation
    • 3. Protein synthesis fidelity: slowing of protein synthesis due to slowing of transcription or translation (specifically elongation). Can be prevented by calorie restriction
    • 4. Calorie restriction: increases rate of transcription of catalase, superoxide dismutase and heat shock protein. Also contributes to Protein DEGRADATION
    • 5. Telomeres: Strehler hypothesis loss of redundant genes (rRNA) contributed to aging. Have NO effect of senescence in Podospora
    • 6. Signal transduction: decrease in cell membrane signaling
  8. Apoptosis Theory
    • Systemic and INTRACELLULAR
    • Failure of cells to undergo programmed is thought to cause diseases (cancer)
    • due to inactivation of p53 gene
  9. Phagocytosis Theory
    • Systemic, INTRACELLULAR
    • Loss of Normal surface antigens MARKS them for DESTRUCTION by macrophages
  10. Neuroendocrine Theory
    • Systemic, INTerCELLULAR
    • Loss of negative-feedback homeostasis in neuroendocrine system
    • Evidence comes from reproductive analysis in mammals
  11. Immunological Theory
    • Systemic, INTerCELLULAR
    • Loss of immune regulation
  12. Systemic, INTRACELLULAR theories
    • Metabolic
    • Genetic
    • Apoptosis
    • Phagocytosis
    • Neuroendocrine and Immunological Theories are Systemic, BUT INTercellular