G - Ageing process (not the best lecture)

Question 1

What is the loop of DNA known as at the end of the strand basically to ensure each strand has an end point, known as?

Answer 1

This is the telomere

Question 2

Why is that cells undergo senescence after multiple replications?

Answer 2

This is due to the fact that telomeres shorten after each replication eventually to the stage where it is too short to sustain cell replication

Question 3

Why is it that in diseased states the telomeres tend to shorten quicker?

Answer 3

This is because there is an increased cell turnover meaning the rapid shortening of telomeres before the cell undergoes senescence

Question 4

What is the ribonucleotide protein present in some cells eg immune and stem cells that can re-extend shortened telomeres?

Answer 4

This is telomerase

Question 5

What is one of the likely reasons that telomeres shorten however?

Answer 5

One of these reasons is likely that is to prevent cancer cells from becoming present as these cells will repeatedly divide

Question 6

Damage to DNA causes 4 main cellular responses, what are these responses?

Answer 6

1. Repair
2. Apoptosis
3. Senescence
4. Malignant transformation

Question 7

If there is a lot of damage in a cell – can have the apoptic pathway where the cell will commit suicide

If apoptosis doesnt work, what will happen to the cell?

Answer 7

If this doesnt work then the cell will go into senescence where it basically stops functioning and goes to sleep

Question 8

If the cell is unable to be repaired, unable to go through apoptosis or senescence, what happens to the cell?

Answer 8

The cell will enter malignant transformation ie become cancerous

Question 9

Frailty is known to cause an Increased vulnerability to decompensation after a stressor event

What does this actually mean? (in terms of a fall)

Answer 9

If a healthy person were to fall, they would have a small decrease in their functional ability whereas if a frail person were to fall this would greatly increase their dependence on others for help

Question 10

What are the two tools used to measure fraility in a person?
One is there defecit accumulation

Take a number of system and count how many defecits are per system - what tool is this?

One is their phenotypic wehre key markers are measured?

Answer 10

Deficit accumulation is the Rockwood score - between 0and1 (systems over number of diabilities)

Phenotypic is the Fried score - score of 3 is frail

Question 11

What is the end part of the chromosome?
Why does this end part shorten in cell replication?
What enzyme increases the length of the end part of the chromosome?

What two tests are carried out to measure frailty?

Answer 11

End part of the chromosome is the telomere - it loops round
Shortens during replication so that once it reaches too small a replication length requirement the cell enters senescence

Telomerase can re-extend the telomere

Rockwood test = number of disabilities over systems measured (deficit accumulation)
Phenotypic - Fried score