Molecular Carcinogens— CDK+cyclin

Question 1

What are cyclins

Answer 1

Regulatory proteins that bind to CDK’s and control the cell cycle

Question 2

What are CDK’s

Answer 2

Cyclin- dependant protein kinases, that drive the cell through the cell cycle, and are inactive on their own.

Question 3

CDK-cyclin complex action on target protein

Answer 3

Phosphorylates the crucial target proteins that drive the cell forward through the cell cycle

Question 4

The phase of cell cycle in which cyclin D is active

Answer 4

G1

Question 5

Cdk partner of cyclin D

Answer 5

Cdk 4/6

Question 6

What protein does G1 phase
CDK-cyclin complex activate

Answer 6

Retinoblastoma (Rb) protein

Question 7

Phosphorylation of Rb protein leads to release of what transcription factors

Answer 7

E2F

Question 8

E2F causes what

Answer 8

Leads to transcription of genes necessary for S-phase entry

Question 9

Cyclin D mechanism

Answer 9

1. In G1 phase
2. Cdk partner — cdk 4/6
3. CyclinD-Cdk4/6 complex phosphorylates the Rb protein
4. This leads to release of E2F transcription factors
5. Promotes transcription of genes necessary for S-phase entry

Question 10

Over-expression of cyclin D leads to

Answer 10

Excessive phosphorylation of Rb protein
Bypassing the G1/S phase checkpoint
Promotes tumour development

Question 11

what causes tumour development in G1 phase

Answer 11

Over expression of cyclin D leads to ^ phosphorylation of Rb protein
Therefore cells by pass the G1/S checkpoint
Tumour development

Question 12

What is maturation promoting factor

Answer 12

Cyclin B - cdk 1 complex