Cell Proliferation SAQs

Question 1

Briefly describe the differences between embroynic and stomatic cell cycles in animals

Answer 1

Embryonic: division without cell growth. rapid and synchronous division

Stomatic: division with cell growth

Question 2

What is the restriction point in the eukaryotic cell cycle?

Answer 2

Regulatory mechanism in late G1 that shifts cells between proliferative and quiescent states
Cancer cells may have lost their restriction point

Question 3

How does proteolysis occur in humans?

Answer 3

Polyubquitination
Once polyubiqutated, it is recognised and subjected to proteolsysis (breakdown of protein)

Question 4

What is the APC?

Answer 4

Anaphase Promoting Complex
Is needed for the transition from metaphase to anaphase

Question 5

What does the APC do?

Answer 5

Two processes:
- Ubiquitation of securin, which activates the seperase enzyme
- Destruction of S and M cyclins, allowing progression to G1in the subsequent cell cycle