Mitosis and Cell Cycle 1 and 2

Question 1

goal of somatic cell cycle

Answer 1

produce two cells (geneticaly) identical to the first cell

Question 2

four phases of cell cycle

Answer 2

G1 S G2 M

Question 3

S phase

Answer 3

synthesis

Question 4

M phase

Answer 4

mitosis

segregation of material duplicated in S phase

Question 5

G1 and G2 phases

Answer 5

gap phases

cycle regulation of subsequent phase

Question 6

G0

Answer 6

resting phase before G1 (quiescent state)

Question 7

Interphase

Answer 7

all phases except mitosis

G1, S, and G2

Question 8

restriction point

Answer 8

forces commitment to synthesis through G1 phase

Question 9

size homeostasis

Answer 9

cell growth must complement cell division

goes away in embryo, cells get smaller as they divide

Question 10

cyclin-dependent kinase (CDK)

Answer 10

protein kinase that takes gamma phosphate from ATP and adds it to residues to regulate activity (serine, threonine, and tyrosine)

CDK only does serine/threonine

Question 11

phosphorylation action

Answer 11

either activates or inhibits activity

Question 12

CDK subunits

Answer 12

monomeric Cdk is inactive, always present in cell

cyclin subunit activates Cdk (variably present)

G0 cell phase has no cyclin

Question 13

cyclin

Answer 13

different cyclins exist at different points in the cell cycle to drive different activities

Question 14

growth factor GF

Answer 14

pushes cell from G0 to G1

Question 15

inhibitors

Answer 15

negative regulation

Question 16

inhibit inhibitor

Answer 16

turn off deregulation to get up regulation

Question 17

RB

Answer 17

inhibitor to entering cell cycle

Question 18

CDK cycle

Answer 18

CDK 2, 4, and 6 interact with different kinases to perform different functions in the cell cycleRB

Question 19

Rb (Retinoblastoma protein) Regulation

Answer 19

fff

Question 20

CDI

Answer 20

CDK Inhibitors

Question 21

CDI action

Answer 21

bind to CDK/cyclin complex to inhibit action

Question 22

CDI relevance to cancer

Answer 22

frequently mutated, p16 missing in melanoma

p53 mutated in almost half of all cancers

Question 23

meaning of the numbers in protein names

Answer 23

weight in kD, i.e. p27 means the 27kD p protein

Question 24

cancer action of inhibitors

Answer 24

failed inhibitor leads to overexpression of a regulated protein

Question 25

origin of replication

Answer 25

site on chromosome where replication begins ~100k in human genome, not uniformly distributed

Question 26

okazaki fragments

Answer 26

lagging strand DNA segments synthesized from lots of RNA primers

Question 27

how do you get faster DNA replication

Answer 27

use more replication origins (i.e., rapid growth cell types, embryos)

Question 28

reinitiation

Answer 28

using the same origin twice in one cycle, never seen, would lead to an extra chromosome

Question 29

Orc

Answer 29

Origin recognizing complex

Question 30

Orc1-6

Answer 30

gloms onto DNA at origin, becomes a "landing pad" for Cdt1 and Cdc6, brings in hexomeric complex DNA helicase (Mcm2-7)

Question 31

cell cycle checkpoints

Answer 31

size? Make DNA? New DNA? Spindle?

Question 32

defective checkpoints

Answer 32

cancerous cell growth

Question 33

hodgkins lymphoma

Answer 33

secondary cancer from original treatment

Question 34

DNA checkpoint regulation

Answer 34

monitor DNA for damage or block replication entirely

Question 35

DNA Damage regulator

Answer 35

Rad17 binds to DNA damage | sends a signal to ATM and ATR to block P53/p21

Question 36

P53/p21

Answer 36

inhibit CDK in DNA damage regulatory steps inhibits all in cyclin dependent kinase activity in cell

Question 37

Types of DNA checkpoint mechanisms

Answer 37

Double strand breaks stalled replication forks DNA mismatches nucleotide damage

Question 38

folate function

Answer 38

needed for making nucleotides | not enough folate leads to poor DNA replication

Question 39

BRCA2

Answer 39

tumor suppressor, senses DNA damage and blocks cell cycle missing one copy in the 5% of women getting breast cancer (checkpoint mechanism)

Question 40

cancer cell achilles heel

Answer 40

inherent instability of cell due to checkpoint failures

Question 41

crossover during mitosis

Answer 41

infrequent, not for reorganization of genetic material, but a tool for DNA repair

Question 42

crossover during meiosis

Answer 42

frequent (1000x mitosis), for genetic recombination