division

Question 1

what is cell cycle

Answer 1

cell growth and chromosome replication 
chromosome segregation 
division 
thus 
duplication 
division 
co ordination

Question 2

what are cell cycle phases

Answer 2

m mitosis
g1
s 
g2 
(g1 s g2 =interphase)
g0- non dividing like nuerones

Question 3

where. are the check points in the cycle

Answer 3

g1 - g2- mitosis

Question 4

what is checked per checkpoint

Answer 4

g1- environment (nutrients, growth factors)
g2- if dna has replicated
and if the damage has repaired /
m- are the chromosomes attache to the mitotic spindle

Question 5

what happens when the cycle pauses

Answer 5

dna repair

undergo apoptosis

Question 6

how cells leave g0

Answer 6

response from growth factors from g0 to g1

Question 7

why are there multiple checkpoints

Answer 7

prevent disastrous progression

Question 8

what happens when growth factor binds to gf receptor

Answer 8

lots of enzymes involved 
amplify signal 
protein synthesis increases 
protein degradation decreases
so the cel can double in size

Question 9

what is c-Myc

Answer 9

transciption factor

stimulates expression of cell cycle genes

Question 10

function if c-Myc

Answer 10

promotes g0 to g1

overexpressed in many tumours

Question 11

cdks

Answer 11

invloves into phosphyratlion and dephospharylation
involved in signalling
control cells

Question 12

how cdks activated

Answer 12

only active when cyclin is bound

Question 13

what does cell cyle entry require

Answer 13

Cdk 4/6:cyclin D complex

Question 14

protien kinase cascade leads to

Answer 14

signal amplification
diversification - activate other pathways
opportunity for regulation

Question 15

cdk cyclin dependent kinases activity is regulated by what

Answer 15

interaction and phosphyralytion

Question 16

how cdk are activated

Answer 16

1) cylclin binds
multiple phosphyatlion reactions at both sites ( active and inhibotory)
phosphates removes inhibotory phosphate
is activated

Question 17

what does active cdk do

Answer 17

drives cell cycle to progress to next step 
e.g. 
s cylin to s phase 
m cyclin to m phase 
gives timimng and direction to cycle

Question 18

how are cdk inactivated

Answer 18

uniquiatyltion
ubiquitones are stuck to protiens that they want to degraded e.g. teh cyclin
they result in inactive cdk

Question 19

retinoblastoma is what

Answer 19

a tumor supressor,

Question 20

how it works

Answer 20

active rb sequesters a trasnciption factor in an inactive form
the tf can’t turn genes on for cell cycle prolliferation

Question 21

how does proliferation occur

Answer 21

actiavtion of intracellular signalling leads to production of active cdk
these inactivate rb by phosphorylation
relaseing tf
target genes needed for dna sythesis are produced

Question 22

what does p53 do

Answer 22

arrest cells with dna damage in g1

it activates protien kinase that can activate itself

Question 23

if there is no dna damage what happens

Answer 23

p53 is made then degraded instantly

Question 24

what does p53 induce

Answer 24

p21 by binding to the rehglutatory region on p21
casues transcition of p51 mrna
trasnlated to protien
it binds and sequesters the active cdk

Question 25

what re the 2 tumor supressor

Answer 25

p53 and rb