Cell cycle

Question 1

aneuploidy

Answer 1

when the chromosomal number of a cell
is not a multiple of the haploid number.

In diploid eukaryotic organisms such as humans, after cells progress through the S phase they contain a tetraploid contentof DNA.

Question 2

Cyclin-dependent kinases (cdk)

Answer 2

• binds cyclins

* present throughout the cell cycle

Question 3

Cyclins

Answer 3

• no enzyme activity
• binds cdk
• it is essential to cdk activity
• their amount changes during the cell cycle

Question 4

cyclin +cdk in G1/S

Answer 4

CDK D with cyclin 4 and 6

Question 5

cyclin +cdk in S

Answer 5

CDK E with cyclin 2

Question 6

cyclin +cdk in G2

Answer 6

CDK A cyclin 2 and 1

Question 7

cyclin +cdk in M

Answer 7

CDK B cyclin 1

Question 8

Inhibitors

Answer 8

CDKI inhibits G1 and s

Question 9

G0

Answer 9

If cells are not cycling, they are said to be in G0 phase
and are termed quiescent.
Cells can be recruited into the cycle
from G0 by various influences

Question 10

ATM kinase

Answer 10

Inactivates cdc 25, phoshorylates Cdk 1 and 2 and phosphorylates cdc 25, no G1/S transition

Question 11

APC/ E3 ubiquitin ligase

Answer 11

marks protein for degradation

Question 12

Retinoblastoma

Answer 12

substrate od Cdk 2, when rb bounded to E2F no transcription.

Question 13

Removal of RB

Answer 13

phosphorylation of RB by CDK2, and rb detaches from E2F. replication

Question 14

p53

Answer 14

Tumor supressor
Activated when DNA is damaged, avtivates p21, which inhibits CDK 2.
activated by phosphorylatin
inhibited by mdm

Question 15

Ubiquitin Proteasome System

Answer 15

Proteins are being linked to the polypeptide co-factor, ubiquitin for proteasomal degradation.