Which sequence best describes apoptosis at the G1 checkpoint?

The correct answer is "Cdk/cyclin complex is inhibited→ p53 levels rise → p21 production increase".

Explanation:

The missing options of this question are:

A. p53 levels rise → p21 production increase → Cdk/cyclin complex is inhibited

B. p21 production increase → Cdk/cyclin complex is inhibited→ p53 levels rise

C. Cdk/cyclin complex is inhibited→ p21 production increase → p53 levels rise

D. Cdk/cyclin complex is inhibited→ p53 levels rise → p21 production increase

E. p53 levels rise → Cdk/cyclin complex is inhibited→ p21 production increase

The correct answer is option D. "Cdk/cyclin complex is inhibited→ p53 levels rise → p21 production increase".

Apoptosis is a process at which the cells undergo a programmed death. This mechanisms happens at G1 checkpoint first by the inhibition of Cdk/cyclin complex which causes p53 levels to rise and later, an increment of p21 production. First, a cyclin-dependent kinase inhibitor regulates the inhibition of the Cdk/cyclin complex. This causes p53 levels to rise, since p53 is a direct downstream kinase substrate for CDK. Subsequently, p21 production increase as well since p21 is a inhibitor of cyclin-dependent kinases.

the correct answer is:

a population changes in response to a change in the environment.

succession returns a disturbed

ecosystem to a more stable state. this is also classified into two (2) types:

primary succession and secondary succession. the primary succession arises when

a new land is transformed and a bare rock has been exposed providing an environment

that can be occupied for the first time. while, secondary succession occurs

when a previously occupied environment was disturbed that kills much of all its

community

explanation: