C18 Cell cycle control

Question 1

cell cycle checkpoint control is a feedback regulated (positive/negative) control

Answer 1

negative

Question 2

Cell cycle is controlled by ? activated protein kinases

Answer 2

cyclically

Question 3

Entry into M phase is initiated as ? is activated by appearance of ?

Answer 3

M-cdk ,M- cyclin

Question 4

cdk,cyclin phosphorylation is controlled by these three enzymes

Answer 4

inhibitory kinase, activating kinase, activating phosphatase

Question 5

Activated M-cdk participates in ? which activates other M-cdk

Answer 5

positive feedback loop

Question 6

M-cdk acts to phosphorylate key proteins to drive cell to ?

Answer 6

mitosis

Question 7

S-cdk triggers ?

Answer 7

DNA replication

Question 8

How are cdks turned off

Answer 8

degradation by proteasomes by being marked with ubiquitine

Question 9

Protein that starts signalling of DNA damage by activating protein kinase chk2

Answer 9

ATM

Question 10

Common growth signal

Answer 10

EGF

Question 11

braking mechanism that keeps cell s from proliferating

Answer 11

Rb protein

Question 12

? inhibits growth of myoblasts that form muscle cells

Answer 12

myostatin

Question 13

apoptosis is mediated by intracellular ?

Answer 13

proteolytic cascade

Question 14

apoptosis summary

Answer 14

procapsases activated by proteolytic cleavage to active capsases which activate additional procapsases and ultimately degrade many key proteins

Question 15

Apoptosis is regulated by ? proteins

Answer 15

Bcl-2

Question 16

Inducers of apoptosis

Answer 16

tissue necrosis factor receptor, DNA damage, stress

Question 17

Intrinsic apoptosis

Answer 17

internal cellular damage triggers release of cytochrome c from mitochondria. cyt c activates procaspase-9

Question 18

? or ? influence permeability of mitochondria, releasing cyt c

Answer 18

bad or bax

Question 19

Cancer cells affected genes fall into two classes:

Answer 19

oncogenes and loss of function of tumor supressor genes

Question 20

oncogenes

Answer 20

mutant genes in proliferative genes that result in overexpression of the protein. Normal version called proto-oncogenes. Only one copy of gene must be mutated to become active.

Question 21

? stimulate cell division

Answer 21

mitogens

Question 22

? promote cell survival by suppressing apoptosis

Answer 22

survival factors