Cell Cycle and Apoptosis

These flashcards cover key concepts from the lecture on the cell cycle, cyclins, checkpoints, apoptosis, and their roles in cell homeostasis and cancer.

What are the phases of the cell cycle?

G1 Phase, S Phase, G2 Phase, M Phase.

What do cyclins and cyclin-dependent kinases (Cdks) do?

They work together to orchestrate the timed events of the cell cycle.

How is the cyclin-Cdk complex activated and deactivated?

It is activated by phosphorylation at specific sites and deactivated by the addition of phosphates that inhibit activity.

What triggers the transition from G1 to S phase?

The activation of S-Cdk complex.

What is the role of p53 in the cell cycle?

p53 can stop the cell cycle upon DNA damage by causing expression of p21, which inhibits G1/S-Cdk and S-Cdk complexes.

What are mitogens?

Mitosis-triggering signal molecules that activate cell proliferation genes via Cdks.

What occurs during apoptosis?

It is a programmed cell death that is important for development, tissue homeostasis, and elimination of old or damaged cells.

Which proteins are involved in triggering apoptosis?

Bax and Bak release cytochrome C from mitochondria, activating executioner caspases.

What is the function of the Anaphase-promoting complex (APC)?

It is a ubiquitination enzyme activated by M-Cdk that marks securin for degradation and enables sister chromatid separation.

How do survival factors affect apoptosis?

They suppress apoptosis via anti-apoptotic Bcl2 family members that inhibit pro-apoptotic proteins like Bax and Bak.