lecture 15-17 (Regulation of Eukaryotic cell cycle control and cell division)

Question 1

when cells divide too quickly before reaching its optimum size the daughter cells will become:

Answer 1

too small to stay alive

Question 2

when the cell grow too large before cell division this will cause:

Answer 2

an increase number of cells (improper function)

Question 3

True or False: cells divide all the time

Answer 3

false, only when needed

Question 4

an example of a cell that continuously divides:

Answer 4

cells lining the intestine

Question 5

example of a cell that never divides:

Answer 5

nerve cells

Question 6

how do cells communicate?

Answer 6

using signalling molecules which is induced by the cell receptor

Question 7

what is the function of cell signal?

Answer 7

makes cells respond in different ways and makes it divide

Question 8

when does a cell turn cancerous?

Answer 8

when the cell losses the comunication and divides without command

Question 9

what is the function of signalling pathway?

Answer 9

regulate gene expression, Cytoskeletal organisation and metabolism

Question 10

what are main events in cell cycle?

Answer 10

1) s-phase: chromosomes are duplicated (DNA)
2) M-phase: chromosomal distribution

Question 11

what is the result of cell division before proper DNA replication?

Answer 11

one daughter cell will have less chromosomes

Question 12

how does the cell control chromosome replication and segregation?

Answer 12

by check points that prevent the initiation of the following step unless the earlier step have been completed.

Question 13

DNA replication is initiated when ____ is activiated

Answer 13

cdk2 & cyclin A

Question 14

what is the function of cyclin D + cdk 4 & 6?

Answer 14

regulates Rb which inactivates the E2F by binding with

Question 15

why is E2F important?

Answer 15

because it transcrip many genes required for G1, S, & M phase

Question 16

what is the function of cyclin E and CDK 2?

Answer 16

Cyclin E/CDK2 phosphorylates retinoblastoma protein (Rb) to promote G1 progression.&raquo_space;> activate postive feedback from E2F

Question 17

when E2F is activated it produces which cyclin:

Answer 17

cyclin E
cyclin A
cyclin B

Question 18

True or False: CDK are protein and cyclin are enzymes

Answer 18

false, cyclin are protein and CDK are enzymes

Question 19

what is the relation between the activity of Rb and E2F transcription factor?

Answer 19

when Rb is activited it will inactive E2F but when Rb is phosphorlated it will inactive and active E2F transcription

Question 20

what is the function of cdk inhibitors (p15/p16/p21/p27)?

Answer 20

it blocks the cell cycle progression from G1 to S phase

Question 21

where does the cyclin and cdk of the s phase accumlate?

Answer 21

in the G1 phase

Question 22

in G1 phase what happens to cdk 2 (s phase cdk)

Answer 22

it will bound to an inhibitor that will be destructed to initiate the s-phase

Question 23

how does the inhibitors degrade?

Answer 23

it will be phosphorylated by cyclin E - CDK2 and degraded by proteasome

Question 24

what is the name of the s-phase inhibitor in yeast?

Answer 24

Sic 1

Question 25

True or False: the initiation factors cannot initiate when phosphorylated

Answer 25

TRUE

Question 26

The activation of ———- causes the initiation factors to become unphosphorylated giving it function

Answer 26

cdc 14 phosphatase

Question 27

__________ triggers degradation of cyclin B

Answer 27

APC/C-Cdh1

Question 28

what is the function of CDC25 enzyme?

Answer 28

activate M-CDK by removing the inhibitory phosphates (cannot happen unless DNA replicates

Question 29

which phase will the M phase-promoting factor (MPF) be activated?

Answer 29

at the end of S-phase

Question 30

APC/C and cdc20 complex causes:

Answer 30

the degradation of securin and the release of separase to breakdown cohesion ring

Question 31

APC/C and cdh1 complex causes:

Answer 31

the degradation of cyclin B to complete mitosis (M-phase)

Question 32

what is the function of Mitotic cyclin and CDK:

Answer 32

phosphorylate many proteins to progress in mitosis

Question 33

function of cdc 14

Answer 33

dephosphorylate all phosphorylated proteins in mitosis

Question 34

______ and ________ are proteins that activates in the site of damage for repair.

Answer 34

ATM and ATR

Question 35

cycling of MPF (mitosis) activity in Xenopus egg depends on:

Answer 35

the synthesis and degradation of cyclin B