1 Biology of Aging Questions to be addressed… 1. Why do all living things age?  Maintenance and repair theory 2. Why do different species age at different rates?  Evolutionary theory of aging 3. What are the major theories that explain the aging process?  Free radical theory  Glucose cross-linking theory  Telomere theory 4. What can be done to slow the aging process?  Caloric restriction  Dietary supplements  Exercise 5. How can high levels of cognitive function be maintained as we age?

2 1.Why do all living things age? Maintenance and repair theory…. Each species has its own “repair budget”  Mice: 2 years  Dogs: 11 years,  Humans: 75 – 80 years  Most Turtles: > 30 years  Parrots: > 75 years  Certain rockfish: >150 years  Bristle cone pine trees: >5000 years

3 1. Why do all living things age? (cont.) Maintenance and repair is energetically “expensive”  But so is reproduction!  The cost of reproduction vs. the cost of repair For most species to survive energy dedicated towards maintenance and repair decreases over time.  The end result? ……. Aging

4 2. Why Do Different Species Age at Different Rates? Evolutionary theory (Natural Selection)…  If an organism differs in any particular behavior or way in doing things that results in the production of more offspring, then they will be the ones whose genes survive. How is aging affected by natural selection?  Organisms that live in a “dangerous environment age quickly” and vice versa.  Opossums of the mainland and Sapolo Island  Bristle cone pine vs other pine species  Rock fish vs. other fish

5 3. Theories that explain the aging process a)Free radical theory…  The oxygen we breath is slowly killing us  As mitochondria create ATP during aerobic respiration, some of the electrons passing through the carrier proteins of the electron transport system leak out and react with oxygen molecules to produce oxygen free radicals, O 2 -, (superoxdide radicals).  Superoxide radicals are very reactive and destroy most every molecule it makes contact with.  Benefits of….  SOD and Catalase (SOD = superoxide dismutase)  Vitamins C and E

6 Roles of SOD and Catalase SOD converts the superoxide radical to hydrogen peroxide: SOD-Cu 1+ + O H +  H 2 O 2 + SOD-Cu 2+ Catalase deactivates hydrogen peroxide: 2 H 2 O 2  2 H 2 O + O 2 If not deactivated, H 2 O 2 moves to the nucleus of the cell where iron ions catalyze the production of hydroxyl radicals: H 2 O 2  2 o OH Hydroxyl radical: Via a redox chain reaction it destroys DNA and most everything around it !!

7 3. Theories that explain the aging process (cont.) b)Glucose cross-linking theory  Glucose is slowly killing us….  Diabetics age much quicker  Glucose cross links with proteins making them less elastic and less flexible. E.g. Baked chicken, overcooked meat Impacts: Eyes, lungs, skin, blood vessels, etc. c)Telomere theory of aging

8  Caloric restriction  Dietary supplements  Exercise 4.What can be done to slow the aging process?

9 5.How can high levels of cognitive function be maintained as we age? Challenge yourself intellectually  Lead a “healthful lifestyle  Exercise regularly  Decrease Stress  Have a flexible personality: Don’t try to change the things you can’t control