Question

Irradiated mammalian cells usually stop dividing and arrest at a GI checkpoint. Place the following events in the order in which they occur.

1. production of p21
2. DNA damage
3. inhibition of cyclin-Cdk complexes
4. accumulation and activation of p53
A) 1,2,3,4,
B) 3,1,4,2
C) 2,4,1,3
D) 4,3,2,1
E) 1,4,3,2

Answer 1

The correct order of events in irradiated mammalian cells that stop dividing and arrest at a GI checkpoint is: DNA damage, accumulation and activation of p53, production of p21, and inhibition of cyclin-Cdk complexes.

Step-by-step explanation:

1. 2. DNA damage
2. 4. accumulation and activation of p53
3. 1. production of p21
4. 3. inhibition of cyclin-Cdk complexes

The correct order of the events in irradiated mammalian cells that stop dividing and arrest at a GI checkpoint is: 2. DNA damage, 4. accumulation and activation of p53, 1. production of p21, and 3. inhibition of cyclin-Cdk complexes. When DNA damage is detected, it triggers the accumulation and activation of p53. As p53 levels rise, the production of p21 is triggered, which inhibits the activity of the cyclin-Cdk complexes, leading to cell cycle arrest.