FOM 7.3.1

Question 1

What is the role of G1?

Answer 1

Cell growth, make stuff, longest phase, prevents prod of smaller daughter cells

Question 2

What is the role of S?

Answer 2

DNA replication

Question 3

What is the role of G2?

Answer 3

Checkpoints (The Accountant)

Question 4

What is the role of M phase?

Answer 4

Separation of the cell into daughter cells (PMAT)

Question 5

What are the three essential functions of cell cycle?

Answer 5

Propagation, Replace dead cells, Increase specific cell types

Question 6

On which phase do mitogens act? Mitogens increase expression of what gene regulatory protein? What cyclin is up regulated as a result?

Answer 6

G1; Myc; Cyclin D

Question 7

What are some characteristics of cells in the G1 phase?

Answer 7

Cell energy high, increased protein synthesis, some organelle duplication, increased cell size

Question 8

What is sensed by mTOR? What does it initiate?

Answer 8

Nutrients (Branched core AA); protein synthesis

Question 9

What is the inhibitor of mTOR?

Answer 9

Rabamycin

Question 10

What is the catchy slogan for S phase?

Answer 10

Making more of a good thing

Question 11

Pair ORC, MCM, Licensing factors, DNA pol α, DNA pol δ/ε, and clamping proteins with their corresponding phase.

Answer 11

Look at picture

Question 12

Describe the western blot of CDC6, CDT1, and geminin.

Answer 12

Look at picture

Question 13

What are the functions of cohesions?

Answer 13

Wraps around newly synthesized DNA (sister chromatids during S phase), acts as a cage, can’t go through M phase until cage is removed (broken down late in mitosis)

Question 14

What are the phases of M phase?

Answer 14

PMAT (Prophase, Metaphase, Anaphase, Telophase) Hint: Pittsburg Made A Touchdown

Question 15

Name the three positive and three negatives cell cycle regulators.

Answer 15

Pos: Cyclins, CDK, protein degradation Neg: Txn Repressors, CDKI, Check points

Question 16

Where do cyclins get their name?

Answer 16

They are proteins that are expressed in cycles.

Question 17

Make the chart that compares phase of cell cycle to Cyclins, CDK partner, and function.

Answer 17

Look at table

Question 18

Describe the two positive feedback methods of an activated Cdk.

Answer 18

1) Phosphorylating a phosphatase (cdc25), which increases removal of an inhibitory phosphate group 2) Inhibiting the Cdk-inhibitory kinase

Question 19

How does CDK1 initiate M phase? (4)

Answer 19

1) Assemble mitotic spindle 2) Chromosome condensation 3) Nuclear envelope breakdown 4) Actin cytoskeleton rearrangement

Question 20

What are the three mechanisms for inactivating a Cdk?

Answer 20

1) inhibitory phosphorylation 2) inhibitory protein 3) no cyclin (Lauren, you should already know this!)

Question 21

What are the two ubiquitin ligases of the cell cycle?

Answer 21

SCF and APC/C

Question 22

Describe how the composition of ubiquitin ligases aids in their ability to alter their activity.

Answer 22

The ligases have four different protein portions (Catalytic, Scaffold, Adaptor, Variable Component), which allows for a mix-and-match system that can alter function of degradation

Question 23

When is the SCF complex most active?

Answer 23

G1/S push cell through cell cycle

Question 24

APC/C complex is the key regulator of which phase?

Answer 24

M phase tags cyclin and targets for proteosome

Question 25

APC/C is also used in which process that is unique to M phase?

Answer 25

Sister chromatid seperation (APC/C marks securin for degradation, which allows separase to cleave the cohesion complex)

Question 26

What is the role of mitogens?

Answer 26

Interact with surface receptor and MAPK cascade. Leads to activation of cyclin Ds which activate G1-CDK.

Question 27

What is the role of mTOR?

Answer 27

It is involved in regulation of cell size by sensing nutrients. This also activates target proteins that push the cell through the cycle.

Question 28

When are Cdc6 levels highest and lowest?

Answer 28

Cdc6 rises in G1 through S phase and is degraded in G2 to prevent multiple rounds of replication

Question 29

When are cdt1 levels highest and lowest?

Answer 29

cdt1 is highest during G1 and is degraded during S phase

Question 30

What does Geminin do?

Answer 30

It in an inhibitor of cdt1 and increases its levels in late S and G2 phase

Question 31

What does cyclin D do?

Answer 31

It combines to made G1-CDK which promotes passage through G1 and inhibits Rb

Question 32

What does Cyclin E do?

Answer 32

It combines to make G1/S-CDK which commits the cell to replicate DNA

Question 33

What does cyclin A do?

Answer 33

It combines to make S-CDK which stimulates chromosonal duplication

Question 34

What does cyclin B do?

Answer 34

It combines to make M-CDK which stimulates entry into M phase at the end of G2

Question 35

What is the process of activation of CDK1?

Answer 35

Dephosphorylation of CDK1 by Cdc25 leads to activation of it to let it work on amplification process

Question 36

What are some methods of CDK1 regulation?

Answer 36

Inhibiting phosphorylation, and degrading the cyclin or having none present

Question 37

DNA damage leads to what ?

Answer 37

Activation of p53 which leads to increased Chk1 which leads to inactivation of CDK1 and arrest in cell growth in G2/M phase

Question 38

What is the role of retinoblastoma?

Answer 38

It is inhibiting E2F in normal state and then is acted upon by cyclin D which has it get rid of HDACs, then the G1/S-CDK will act on it to separate the Rb from E2F leading to an active E2F.

Question 39

Gaurdasil is 98% against HPV. It specifically fights off the HPV that have viral protein E7. What is so problematic about E7?

Answer 39

E7 binds to and leads to the degradation of Rb proteins (loss of the G1/S check point)