Theories Of Ageing

Question 0

What are antagonistic pleiotropic genes?

Answer 0

Genes have two or more effects on the phenotype and are retained due to their good effect but have a bad late effect which contributes to ageing

Question 1

What are the non adaptive evolutionary theories of ageing?

Answer 1

Antagonistic pleiotropic genes

Disposable soma theory

Question 2

What is the disposable soma theory?

Answer 2

Proposes that the rate of ageing is determined by the investment in self maintenance and to ensure success, the survival of genes should be ensured in the most efficient way.
The amount of energy expended on the various possibilities will depend on the ecological niche occupied by that organism.
Result in species specific longevity.

Question 3

What does the neuroendocrine theory suggest in ageing?

Answer 3

Functional decrease in neurones and associated hormones is central to ageing process

Question 4

What does the Hayflick phenomenon suggest?

Answer 4

Fibroblast grown in culture undergo a set of number of divisions and then stop (biological clock) with more divisions taking place of from younger source.
HeLa cell line from cancerous breast shows unlimited division

Question 5

What are heat shock proteins?

Answer 5

Produced at a time of cell stress
Dissemble damaged proteins and transport in new
Reduced production with age
Decreased ability to cope with stress leads to ageing

Question 6

Where are gerontoges?

Answer 6

Genes that have been identifies which can shorten and lengthen life. Genes whose altered activity influences ageing and longevity
Likely it be involved in repair pathways

Question 7

What are telomeres?

Answer 7

Regions of highly repetitive DNA at the end of a linear chromosome which stabilise it during cell division
Shorten with each division and there is a critical length at which no further divisions can occur

Question 8

What is the free radical theory of ageing?

Answer 8

Highly reactive chemical compounds arise from enzymatic and non enzymatic reactions which damage cellular DNA

Question 9

What is the mitochondrial theory of ageing?

Answer 9

Ageing due to mitochondrial DNA damage
High exposure to O2 radicals
No protein coat to mitochondrial DNA
Genetic mitochondrial dysfunction syndromes mimic ageing