Mechanisms Of Ageing

Question 1

What are the four examples of evidence for programmed ageing?

Answer 1

1. Species-specific lifespan
2. Hayflick limit
3. Progeria
4. Gerontogenes

Question 2

What is the species specific maximum lifespan?

Answer 2

Different species are programmed to live for a period of time

Question 3

What is the Hayflick limit?

Answer 3

Limited cell division - cells can only divide a certain number of times then they plateau
Animals which live longer have more cell population doubling than in animals which have a shorter lifespan

Question 4

What is the enzyme which repairs telomeres?

Answer 4

Telomerase

Question 5

Which types of cells contain telomerase?

Answer 5

Stem cells
Sperm cells
Cancer cells

Question 6

What is Progeria?

Answer 6

Fast ageing syndromes e.g. Warner’s syndrome

Question 7

What is the mutation found in Werner’s syndrome?

Answer 7

Mutation in WRN gene which encodes for helicase which means DNA cannot unzip for repair, DNA and protein synthesis etc.

Question 8

What are gerontogenes?

Answer 8

Genes which have an affect on lifespan, when mutated or their expression is changed

Question 9

Which gene changes can increase longevity?

Answer 9

• AGE-1 and daf genes

- Additional genes to increase antioxidants

Question 10

How does AGE-1 and daf increase lifespan?

Answer 10

Mutation stops normal effects of insulin in cells

Question 11

Which variant is associated with late onset Alzheimer’s disease?

Answer 11

APOE4

Question 12

Which organelle produces reactive oxygen species?

Answer 12

Mitochondria

Question 13

What gets oxidised by reactive oxygen species?

Answer 13

Mitochondria
Lipids
Protein
DNA

Question 14

What is the Maillard reaction?

Answer 14

Spontaneous chemical reaction between sugars and protein, increased by ROS

Question 15

What protects against reactive oxygen species?

Answer 15

Antioxidants

Question 16

What are antioxidants?

Answer 16

Any substance, when present in low concentrations compared with those of an oxidisable substrate, significantly delays or prevents oxidation of that substrate

Question 17

Name an antioxidant

Answer 17

Superoxide dismutase which converts superoxide to hydrogen peroxide
Catalase and glutathione peroxide convert hydrogen peroxide to water and oxygen

Question 18

What is oxidative stress?

Answer 18

Imbalance between reactive oxygen species and antioxidants