Biology of Aging
Questions to be addressed…
1.
Why do all living things age?

2.
Why do different species age at different rates?

3.


Free radical theory
Glucose cross-linking theory
Telomere theory
What can be done to slow the aging process?



5.
Evolutionary theory of aging
What are the major theories that explain the aging process?

4.
Maintenance and repair theory
Caloric restriction
Dietary supplements
Exercise
How can high levels of cognitive function be maintained as we
age?
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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
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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
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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
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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, O2-,
(superoxdide radicals).
Superoxide radicals are very reactive and destroy most
every molecule it makes contact with.
Benefits of….


SOD and Catalase
Vitamins C and E
(SOD = superoxide dismutase)
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Roles of SOD and Catalase

SOD converts the superoxide radical to hydrogen peroxide:
SOD-Cu1+ + O2- + 2 H+  H2O2

+ SOD-Cu2+
Catalase deactivates hydrogen peroxide:
2 H2O2  2 H2O + O2

If not deactivated, H2O2 moves to the nucleus of the cell
where iron ions catalyze the production of hydroxyl radicals:
H2O2  2 OH
o

Hydroxyl radical: Via a redox chain reaction it destroys
DNA and most everything around it !!
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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
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4. What can be done to slow the
aging process?



Caloric restriction
Dietary supplements
Exercise
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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
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