Cell Proliferation

Question 0

Checkpoint of cell cycle

Answer 0

1. Restriction checkpoint (cell size, mitogens available)
2. G1 DNA damage checkpoint (DNA integrity)
3. IntraS DNA damage checkpoint (one copy of DNA)
4. G2 DNA damage checkpoint
5. Spindle assembly checkpoint

Question 1

What happens during interphase

Answer 1

Receives nutrients 
Synthesizes RNA 
Produces proteins
Increases in size 
Copies DNA

Question 2

What phase does proof reading happen

Answer 2

G2

Question 3

Classes of CDK inhibitors

Answer 3

INK - binary inhibitors

Cip/Kip - ternary inhibitors

Question 4

G1-S transition

Answer 4

Stimulated by mitogens
Cyclin D produced and CDK 4/6 activated
Phosphorylation of pRB
pRB releases E2F.
Cyclin E is synthesized and CDK 2 is activated
CyclinE/CDK2 complex further phosphorylates pRB
Genes required for DNA synthesis -> S phase.

Question 5

G2-M transition

Answer 5

Cyclin B1/CDK1 kept in inactive form by myt1(thr 14) and wee1(thr15) [kinases]
CDC25 phosphotase activates thr14/15 dephosphorylated
Cellular proteins now phosphorylated.
Nuclear envelope breakdown
Chromosome condensation
Spindle formation
Cell shape changes