Cell Cycle

Question 1

___ levels are constant but its activity fluctuate. But, ____ levels are fluctuate.

Answer 1

CDKs

Cyclin

Question 2

CDK is dependent on ___

Answer 2

Cyclin

Question 3

___ is the heart of the cell-cycle control system

Answer 3

CDKs

Question 4

How does CDK-Cycling activity get activated?

Answer 4

Cyclin binds to the inactive CDK, the T-loop moves away from the active site. CDK is phosphorylated by CAK and it is fully activated.

Question 5

___ fully activates CDK by phosphorylation while ___ inhibits CDK by phosphorylation

Answer 5

CAK

Wee1 Kinase (reversed by Cdc25) or CKI

Question 6

Name an example of a CKI involves in the G1 phase of the cell cycle and is responsible for diseases like melanoma

Answer 6

INK4A

P53

Question 7

Checkpoint I

Answer 7

“Start”
Cell commits to cell cycle entry
“should I be doing it?”

Question 8

Checkpoint II

Answer 8

G2/M
Is all DNA replication?
Is the environment favorable?

Question 9

Checkpoint III

Answer 9

Metaphase to Anaphase transition

“Is the chromosomes all attached to the spindles?”

Question 10

CDK

Answer 10

Cyclin Dependent Kinases

Question 11

Via proteolysis, SCF is added to CKI to allow?

Answer 11

Activation of S-CDKs by ubiquitating CKI for destruction

Question 12

APC/C does not cause protein phosphorylation but instead____

Answer 12

catalyzes addition of ubiquitin to proteins to cause destruction of securin to allow separation of chromosomes with separase

Question 13

Cohesin is the ___ and securin is the ____

Answer 13

glue

linker or clamp holding it together by inhibiting separase

Question 14

What is the opposite of Cohesin?

Answer 14

Separase

Question 15

What protein activates APC/C?

Answer 15

CDC20

Question 16

APC/C cause destruction of what two proteins?

Answer 16

Securin to allow chromosome to separate

S and M cyclin to allow pause of DNA replication

Question 17

PRE-RCS are created ____ times during ____

Answer 17

Once (until next G1 phase)

G1 phase, NEVER during mitosis