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Biochemistry of Aging

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Biochemistry of Aging

  1. 1. Biochemistry of Aging Presented by Shanzay Annum Malik
  2. 2. Aging • Gradual change in an organism that leads to increased risk of weakness, disease, and death over the entire adult life span of any living thing. • There is a decline in biological functions and in ability to adapt to metabolic stress.
  3. 3. Changes in organs include • reduced immunity, • loss of muscle strength, • decline in memory and cognition, • loss of colour in the hair • elasticity in the skin.
  4. 4. Gerontology and Geriatrics • Gerontology is concerned with the changes that occur between maturity and death along with factors that influence these changes. • Geriatrics focuses on health care of elderly people and promote health by preventing and treating diseases and disabilities in older adults.
  5. 5. Factors of Aging • mitochondrial damage • free radicals • telomeres • apoptosis and necrosis • diseases • other effects
  6. 6. Mitochondria: main unit of chemical power supply • During the synthesis of macroergical bio- molecules(high energy releasing potentials e.g. ATP) free radicals are being produced as the by-product. • Free radicals released in large quantities cause intercellular oxidative stress (e.g. oxidative damage of mitochondria) • damaging mitochondria and cause early apoptosis
  7. 7. Free radical • A molecule that contains one or more unpaired electrons &is capable of independent existence. • Eg : Superoxide H2O2, • hydroperoxy radical (HOO+2 ) • lipid peroxideradical (ROO) • Nitric oxide (NO)
  8. 8. Harmful effect of free radicals • Because of their reactive nature, free radical can provoke inflammation or altered cellular function through • Lipid peroxidation • Protein modification • DNA modification
  9. 9. Lipid peroxidation product: • React with amino acid mainly CYS, HIS,LYS to modify protein structure & function. • Can crosslink lipid in cell membrane interrupting structure & fluidity.
  10. 10. Protein modification • Proteins are major targets of free radical attack because of their high abundance & responsible for most of functional processes. • Free radical causes oxidation & modification of certain amino acid (met, cys,His,try) • ROS may damage protein by fragmentation • net result is loss of biological activity of proteins
  11. 11. DNA modification : • Free radical induced DNA damage includes – strand break. – DNA protein crosslink. – large range of base & sugar modification.
  12. 12. Telomeres • Repetitive DNA sequences at the ends of all human chromosomes • aging cells have shorter telomeres • length differs between species • in humans 8-14kb long
  13. 13. • Telomeres are thought to be the "clock" that regulates how many times an individual cell can divide. • Telomeric sequences shorten each time the DNA replicates. • Once the telomere shrinks to a certain level, the cell can no longer divide. Its metabolism slows down, it ages, and dies
  14. 14. Apoptosis and Necrosis • There are two ways that a cell can die: • Necrosis occurs when a cell is damaged by an external force, such as poison, a bodily injury, an infection or getting cut off from the blood supply (which might occur during a heart attack or stroke). When cells die from necrosis, it's a rather messy affair. The death causes inflammation that can cause further distress or injury within the body.
  15. 15. • Apoptosis or programmed cell death • When a cell is compelled to commit suicide proteins called caspases go into action. • They break down the cellular components needed for survival, • production of enzymes known as DNases, which destroy the DNA in the nucleus of the cell.
  16. 16. Diseases • Progeria • Werner Syndrome
  17. 17. other effects • Stress Effects • Octopus Suicide : The octopus suicide mechanism involves behaviors where Females stop eating and die of starvation
  18. 18. Anti-aging Agents. • Aspirin • Caloric restriction • Exercise • laughing out louder • Resveratrol, a constituent of red wine and grape skins has been found to extend life span
  19. 19. Non aging species • Rougheye Rockfish 205 Years • Lake Sturgeon 152 Years • Aldabra Tortise 152 Years • Koi 226 Years • Bowhead Whale 211 Years