BIOM1060 Lecture Notes - Lecture 42: Telomere, Oxidative Stress, Senescence
BIOM1060 29/05/18
Ageing (part 1)
Ageing
- Structural and functional changes accumulating in organism as result of passage of time
- Gradual accumulation of molecular and cellular damage
Why do humans live so long?
- Diet of calorie-dense foods (don’t need to risk life to collect food)
- Development of skills, language and social structures
- Adaptations provided protection against DNA damage
- Medical intervention
Of all people ho’e eer lied to age , / are currently alie
Programmed ageing theories
- Deliberate deterioration because limited life span results in evolutionary benefits
- Eliminating post-reproductive age individuals = less competition for resources (avoiding
overpopulation) and promotes adaptation
- Ageing strongly affected by range of genes
Damage ageing theories
- Absence of natural selection at post-reproductive stage
- Accumulation of damage to body without evolutionary benefit to repair tissues
o Wear and tear theory: accumulation of damage
▪ Limited number of times cell can divide (final state = senescent)
o Genetic theory: telomeres, genes and epigenetics
▪ Number of cell divisions depends on DNA integrity
▪ Telomeres = repeated DNA sequences at end of linear chromosomes
(shorten with each cell division = telomere shortening)
▪ DNA repair mechanisms
▪ Regulated by epigenetics
o Mitochondrial theory: energy metabolism and oxidative stress
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Document Summary
Structural and functional changes accumulating in organism as result of passage of time. Gradual accumulation of molecular and cellular damage. Diet of calorie-dense foods (don"t need to risk life to collect food) Development of skills, language and social structures. Of all people (cid:449)ho"(cid:448)e e(cid:448)er li(cid:448)ed to age (cid:1010)(cid:1009), (cid:1006)/(cid:1007) are currently ali(cid:448)e. Deliberate deterioration because limited life span results in evolutionary benefits. Eliminating post-reproductive age individuals = less competition for resources (avoiding overpopulation) and promotes adaptation. Ageing strongly affected by range of genes. Absence of natural selection at post-reproductive stage. Women protected from number of diseases by estrogen/progesterone until menopause. Hormones and x linked genes extend life. Disability: reduced mobility, decline in neurological function, disease related assistance. Dependency: most everyday tasks more difficult to achieve. Normal changes with ageing reduce reserve capacity (recover poorly) Ageing = diminished homeostasis and regulation of body systems (cid:858)ageing well(cid:859) Lose weight: obesity increases chronic disease states.
