Lecture 7: Cell Signalling

Question 1

effector

Answer 1

receive signals to change cell behaviour

Question 2

examples of short distance signalling

Answer 2

contact-dependent: 2 cells must very close in order to get the signal to bind to its receptor

paracrine: cell sends out diffusible signals to target cells

Question 3

examples of long distance signalling

Answer 3

endocrine: endocrine cell sends out hormones into the bloodstream

Synaptic: neuron extends an axon to reach target

Question 4

what is necessary for a proper ligand-receptor binding

Answer 4

the receptor is specific to that ligand
the target cell must express the receptor protein
ligand binding activates the receptor

Question 5

T/F.
Signaling and binding is irreversible

Answer 5

false. it is reversible

Question 6

what mechanisms mediate intracellular signalling

Answer 6

kinases (adding a phosphate group)
phosphatase (removing a phosphate group)

GTP binding proteins

protein ubiquitination

small molecules

Question 7

does phosphorylation typically turn processes on or off

Answer 7

on but there are some exceptions

Question 8

Ubiquitination

Answer 8

where you add small protein ubiquitin to a target protein

Question 9

GTP binding proteins

Answer 9

these include GEFs and GAPs

GEFS typically exchange GDP for a GTP while GAPs hydrolyze GTP to GDP

Question 10

small molecules (secondary messengers)

Answer 10

produced after the initial signal to amplify it

Question 11

which type of signalling is faster, endocrine or synaptic

Answer 11

synaptic is much faster