Ageing

Question 1

Define telomeres.

Answer 1

Biochemical process of ageing -> Telomeres; are repeated DNA sequences at the end of chromosomes. After every mitosis, they shorten by 50-200 base pairs. Once too short - cell division cannot occur. (Telomere length shortens in leukocytes as we age. Neurons do not divide, but still age.)

Question 2

What is the hayflick limit?

Answer 2

Hayflick limit; is where cells in culture divide a limited number of times, before they deteriorate.(the limit is less in cells from older animals). Limit is at around 50-60.

Question 3

Define free radicals. Examples?

Answer 3

Free radical have unpaired electrons, so are very active. oxygen based free radical (i.e. oxidants) include H2O2, OH-, and O2-. Most are waste products of aerobic mitochondrial ATP production or irradiation.

Question 4

What enzymes prevent oxidative stress?

Answer 4

Several enzymes prevent oxidative stress (e.g. superoxide dismutase).

Question 5

In regards to free radicals what decreases in age?

Answer 5

Oxidative stress increase, affecting DNA proteins and prostaglandins and anti-oxidant enzyme function decreases in age.

Question 6

Describe age antioxidant theory.

Question 7

What enzymes eliminate ROS?

Answer 7

Superoxide dismutase, catalase, peroxidase, glutathione (GSH).