W6 Cell Signalling

Question 1

how do cells know when to move or proliferate

Answer 1

signals

Question 2

What happens when the signal reaches a cell

Answer 2

intracellular biochemical reactions

Question 3

what is spatial regulation

Answer 3

which specific cells/organ

Question 4

what is temporal regulation

Answer 4

when processes should happen in a cell

Question 5

how do cell signals get into the cell

Answer 5

gap junctions

Question 6

how do adjacent cells communicate

Answer 6

direct cytoplasmic communication

Question 7

what are connexons

Question 8

what are connexons made of

Answer 8

6 connexins

Question 9

what are lots of cell to cell channels

Answer 9

gap junction plagues

Question 10

what are connexins made of

Answer 10

4 transmembrane domains (M)
2 extracellular loops (E)
1 intracellular loop (CL)
N + C terminus

Question 11

how do hydrophobic ligand enter

Answer 11

via plasma membrane

Question 12

why do hydrophilic ligands bind to receptors out of cell

Answer 12

cant enter the plasma membrane

Question 13

what happens when the hydrophilic ligan binding do

Answer 13

extracellular signal to intracellular signal

Question 14

how does the cell cycle restart

Answer 14

no signals to convert DNA to RNA
no release of p27Kin1

Question 15

why does no p27Kin1 restart cell cycle

Answer 15

cyclin E not inhibited

Question 16

where are intracellular signalling molecules released from

Answer 16

intracellular stores

Question 17

what type of model do intracellular signalling molecules use

Answer 17

2nd messenger model

Question 18

are ligand gated channels active or passive

Answer 18

passive

Question 19

what are GPCRs

Answer 19

g protein coupled receptors

Question 20

what do G proteins do

Answer 20

activate membrane bound effectors

Question 21

when activated what do G proteins bind to

Answer 21

GTP

Question 22

when inactive what do G proteins bind to

Answer 22

GDP

Question 23

How do GPCRs turn off

Answer 23

intrinsic GTPase rebinds to beta gamma subunit

Question 24

what are GPCRs

Answer 24

largest cell signalling receptor

Question 25

what happens in the adenyl cyclase pathway

Answer 25

• cAMp is converted to PKA
• signals target proteins for glucose metabolism

Question 26

how do you stop the adenyl cyclase pathway

Answer 26

add cAMP phosphodiesterase

Question 27

what happens after a molecule is phosphorylated

Answer 27

• increased hydrophilicity
• activates proteins

Question 28

how do you increase kinase activity

Answer 28

autophosphorylation of tyrosine kinase

Question 29

describe the process of MAPKs cascade

Answer 29

• activation of cell surface receptors
• activates Ras protein
• Ras protein activates MEK pathway

Question 30

How can we stop a transmembrane signalling cascade

Answer 30

• inhibit receptors
• stop intracellular signalling proteins

Question 31

describe the process of the PI3K/Akt cascade

Answer 31

• GPCRs is activated by ligands
• activates PI3K
• this recruits Akt
• activated Akt promotes cell growth

Question 32

how to turn off tyrosine kinases receptors

Answer 32

Phosphatases

Question 33

what happens when there’s no signalling cascade pathways

Answer 33

mRNA doesn’t leave nucleus for transcription so less cell growth

Question 34

what does degrading 2nd messenger do

Answer 34

stop transmembrane signalling cascade