Hrenchir - Pharmacology Carrasco - Cell Cyle

Front 1

What is stage G1?

Back 1

sharp increase in RNA & protein synthesis;
cell gearing p for DNA synthesis & mitosis;
cell size increases

Front 2

what is stage S?

Back 2

DNA synthesis
DNA content of cell doubles from 1N to 2N

Front 3

What is stage G2?

Back 3

Gives cell time to ensure DNA replication is complete

allows for further increased cell growth

Front 4

What is M phase?

Back 4

mitosis - segregation of chromosomal material for daughter cells

Front 5

What is Go phase?

Back 5

resting state

cells of higher eukaryotes remain in a socalled resting state in which ther is little protein or DNA syntheis unless some external signal pushes them into G1

Front 6

Why is it important that the G1 checkpoint is activated during G1 phase?>

Back 6

ensures that everything is ready for DNA synthesis.

Front 7

What is the order of the cell cyle?

Back 7

G1 (possibly Go) S G2 M

Front 8

S + G1 what occurs?

Back 8

Induces G1 nuclei to start S phase. Suggests S phase nucleus contains "diffusible factor" that induces DNA replication

Front 9

S + G2 what occurs?

Back 9

The G2 nucleus does not do S phase. Something about G2 phase is refractory to the diffusible factor from S phase.

Front 10

G1 + G2 what occurs?

Back 10

no S or M

Front 11

M + interphase

Back 11

induces inappropriate mitosis

Front 12

T/F diffusible factors promote S or M phase?

Back 12

T

Front 13

T/F The S phase promoting factor doesnt not work on G1 nuclei.

Back 13

The s phase promoting factor only works on G1 nuclei.

Front 14

T/F the M phase promoter works on everything.

Back 14

T

Front 15

What are cyclins?

Back 15

Proteins whose expression levels go up and down during cell cycle progression.

Front 16

What is level of cyclin D throught the cell cycle?

Back 16

conc. increases rapidly during G1 but then plateus and remains constant for the rest of S G2 and M

Front 17

What is the level of Cyclin E throught the cell cycle?

Back 17

half way through the G1 phase it begings to increase, it then peaks at the begining of S and then is zero at the middle of S phase

Front 18

What is the level of cylclin A throught the cell cycle?

Back 18

starts to increase right before S phase and then peaks just before M phase and is zero in the middle of M phase

Front 19

what is the level of cyclin B throught cell cycle?

Back 19

begins to increase in the middle of S phase and then goes to zero at the end of M phase

Front 20

what is cdk?

Back 20

cyclin dependent kinase

Front 21

cdk is inactive untill . . .

Back 21

it is bound by a CYCLIN protein

Front 22

what does cdk do?

Back 22

phosphorylates transcription factors and other cell cycle regulatory protiens

Front 23

why does the amount of active cdk fluctuate?

Back 23

because the level of cyclins fluctuates

Front 24

what do cyclins do?

Back 24

they are regulatory proteins that bind to cdks at specific states of the cell cycle to regulate cell growth.

Front 25

what is the G1 cyclin and what cdk does it bind.

Back 25

cyclin D binds cdk4

Front 26

what is the S cyclin and what cdk does it bind?

Back 26

cyclin E binds cdk2

cyclin A binds cdk2

Front 27

pro-mitotic effect of cyclin/cdks complexes are negatively regulated by?

Back 27

specific "tumor suppressor genes"

Front 28

What are two cell cycle checkpoints?

Back 28

G1 arrest

G2 arrest

Metaphase checkpoint

Front 29

What factors do the checkpoints in the cells consider metaphase?

Back 29

are all chromosomes aligned on spindle?

Front 30

What factors do the checkpoints in the cells consider for G2?

Back 30

Is all DNA replicated

Is environment favorable

Is cell big enough

Front 31

What factors do the checkpoints in the cells consider in G1?

Back 31

Is cell big enough

Is environment favorable

Front 32

What are the three mechanisms of regulating cyclin cdk complexes?

Back 32

desruction (proteolsis) of cyclins

phosphorylation/dephosphorylation of cdks

inhibitory proteins: cyclin dependent kinase inhibitors that bind cdks blocking cyclins

Front 33

what does the cdc2 mutant do?

Back 33

inactivates cdc2 gene

cell fails to pass mitotic entry checkpoint and the cells continue to grow in size

has cdc25 phenotype

Front 34

what does teh cdc2D mutant do?

Back 34

hyperactive cdc2 gene

passes checkpoint prematurely, the cell is abnormally small.

Front 35

How does intracellular levels of p53 damage DNA?

Back 35

high p53 levels avtivates the transcription of the gene encoding teh cdk inhibitor p21

this inhibits the cyclin/cdk ccomplex and may directly inhibit DNA synthese by interactive with PCNA

Front 36

what is PCNA

Back 36

a subunit of DNA polymerase d that may interact with p21 and inhibit DNA synthesis

Front 37

what are p53/ATM often called?

Back 37

gaurdians of the chromosome

Front 38

what does pathophysiology lead to?

Back 38

cancer

Front 39

what happens to p53 is both copies are muated?

Back 39

loose tumor suppressor function of the gene, these mutations of recessive

Front 40

what is p53 an example of?

Back 40

proto-oncogene - a benign cellular gene that uon mutation of disruption of normal function results in a protein that can contribute to evelopment of a transformed cellular phenotype (unregulated cell growth or cancer)

Front 41

what is apoptosis?

Back 41

programed cell death

Front 42

p53 causes cells to undergo what?

Back 42

apoptosis, if mutated cells do not die and continue to proliferate and have the poetential to develop into a cancerous tumor

Front 43

what is the G1 specifically?

Back 43

G1 is entered when the cell senses growth signals or mitogens. These start the process of cell division whcih is linked to cell ize. Proteins and mRNAs are synthesized in G1

Front 44

what is S phase specifically?

Back 44

DNA is synthisized. Many cytotoxic drugs in cancer act here to destroy DNA

Front 45

What is G2/m specifically?

Back 45

cell arranges and checks chromosomes. There is a major checkpoint here that ascertain that DNA replication and chromosomes segregation has successfully occured. If not then cell enters apoptosis.

Front 46

M phase is what specifically?

Back 46

mitosis, chromosomes drawn apart by molecular motors and cell divides. Many cancer drugs like taxol act here freezing the process and causing apoptosis.