cell fate and responding to signals

Question 1

what leads to cell death

Answer 1

no signals or not appropiate one

Question 2

what does the death signal lead to

Answer 2

activation of suicide proteins and the cell dies

Question 3

what does no death signal lead to?

Answer 3

sicicide proteins being inactive and the cell lives, it engulfs the other cells which have been told to die

Question 4

why does cell death need to be controlled?

Answer 4

contain the contents

lysosomes for example would be bad if spilled out

Question 5

what mediates death signals?

Answer 5

specific extracellular ligands that bind to specific cell surface receptors initiating intracellular signals

Question 6

what does CED9 do without death signals

Answer 6

stays active which iactivated other CED proteins

Question 7

what does CD9 do with death signals

Answer 7

becomes inactive

allows other CED proteins to become active and bring about changes in the cell for death

Question 8

what is cell growth

Answer 8

getting bigger and increaasing size
involved synthesis of new proteins and membrane lipids
metabolism
replication of DNA
increase organelles

Question 9

what is growth controlled by?

Answer 9

growth factors
contact with adjacent cells
nutrient availability

Question 10

key features of cell proliferation

Answer 10

replication of DNA and divison o make two daughter cells

follows a growth phase

Question 11

difference between cell growth and proliferation

Answer 11

cell growth doesnt increase cell number

proliferation does

Question 12

describe the positive growth stimulating pathway

Answer 12

growth factor binds to tyrosine-kinase receptor
causes G-protein to phosphylate
protein cascade stimulated
goes to nucleus
tranciptional factor is produced
affects gene expression
proteins made to stimulate cell cycle

Question 13

deescribe the negative growth inhibition pathway

Answer 13

growth inhibition factor binds to a receptor
causes G-protein to be phosphylated
protein-kinase cascade
transciption factor made
can be defective or missing a proteins meanin trasciption cant be activated
cell cycle inhibited and division stopped

Question 14

where do growth signals come in the cycle cycle

Answer 14

G1

Question 15

what is the cell cycle checkpoint?

Answer 15

traacks the pathway and biochemical chechpoints along the way to ensure cells are okay

Question 16

how does the cell cycle progres?

Answer 16

at each stage checkpoints are removed

if they arent, cell knows somethin wrong so cant continue

Question 17

where does the G1 chekcpoint come from?

Answer 17

outside the cell

Question 18

what is cell differentiation

Answer 18

process by whch cells become specialsed types of cells

usually involves tem ceasing to proliferate

Question 19

process of muscle differetiation?

Answer 19

stem cells differentiate into a myoblast
expression of other muscle speicific genes causes more differentiation and proteins to be made
fusion of budles of myoblasts
the cell cycle inhibited and a muscle made

Question 20

one a gene level, how is a muscle made?

Answer 20

signal comes to the gene, stimulates transciption
MyoD protein factor can bind activating lots of things
master control factors then regulate other factors and proteins

Question 21

what type of extercellular inputs can there be?

Answer 21

ECM
cell-cell
hormones
growth factors
cytokines

Question 22

what type of intacellular signals can there be?

Answer 22

protein kinase
cAMP
ion changes
G-proteins

Question 23

what type of cel fates can there be from signals?

Answer 23

growth
survivial
death/ apoptosis
differntiation