Test 1

Question 1

Ligands

Answer 1

signalling molecule

Question 2

how do ligands initiate signal transduction?

Answer 2

ligands bind to a specific receptor protein

Question 3

what is a signal transduction

Answer 3

the conversion of information in a signal into a cellular response

Question 4

autocrine signalling

Answer 4

cells send signals to themselves

secrete signals which bind to specific receptors on their own plasma membranes

role in reinforcing developmental changes

an important component of signalling in the immune system

Question 5

endocrine signalling

Answer 5

hormones

intercellular communication

Question 6

paracrine signalling

Answer 6

signals with short-lived local effects

Question 7

the structure of G - Protein-coupled receptors

Answer 7

7 transmembrane integral membrane proteins

protein spans the membrane 7 times

the specific ligand binds to the extracellular domain - activates G-protein

Question 8

GPCR function

Answer 8

provide a link between receptor, which receives a signal, and effector protein that produces a cellular response

Question 9

How is GPCR activated

Answer 9

1. signalling molecule binds to GPCR molecule causing it to bind to a G-protein
2. G protein exchanges GDP for GTP.
3. G protein dissociates from the receptor and separates into active subunit and beta/upsilon dimer reassociate

Question 10

classes of ligands binding GPCRs

Answer 10

biogenic amines
amino acids
ions
lipids
peptides
proteins
light
odorants

Question 11

Drug targets for GPCRs

Answer 11

beta-agonists
beta antagonists: propanol
Histamine: antihistamines
Muscarinic antagonists: Ipratropium

Question 12

ligand-gated ion channels

Answer 12

transmembrane ion-channel proteins

Question 13

How do ligand-gated ion channels function?

Answer 13

1. agonist binding to cleft causes the channel to open

2. ions pass through into cytosol

Question 14

what ions are ligand gated ion channels they associated with?

Answer 14

Na+
K+
Ca2+
Cl-

Question 15

activation of ligand gated ion channels

Answer 15

changes membrane potential

Question 16

common drug targets of ligand gated ion channels

Answer 16

GABA A receptors: benzodiazepines

Glutamate receptors: ketamine

Question 17

endogenous ligands

Answer 17

something produced by the body

Question 18

where are nuclear receptors located?

Answer 18

inside cytoplasm

Question 19

features of nuclear receptors

Answer 19

1. lipid-soluble

2. can cross plasma membrane to intracellular steroid receptor.

Question 20

the function of nuclear receptors

Answer 20

1. hormone-receptor complex translocates to the nucleus

2. hormone-receptor complex binds to DNA and regulates transcription

Question 21

receptor tyrosine kinases

Answer 21

receptors which span the cell membrane

regulate cellular growth processes

Question 22

structure of receptor tyrosine kinases

Answer 22

1. monomers

2. cytosolic domain has tyrosine residues bound to it

Question 23

what are receptor tyrosine kinases activated by?

Answer 23

peptide hormones/growth factors

2 receptor tyrosine kinases needed to be activated and dimerise.

Question 24

receptor tyrosine kinases signalling events

Answer 24

1. extracellular ligand binds to the binding site
2. 2 ligands bind and 2 rtk monomers dimerise in order for rtk to fully activate
3. activation of tyrosine molecules which phosphorylate
4. phosphorylated tyrosines phosphorylate and activated intracellular signalling proteins to cause a cellular response.