CTCS Quiz 3

Question 1

What is the distance between pre and post-neuromuscular junction membranes? Is this enough to prevent a flow of current?

Answer 1

20nm. Yes.

Question 2

What type of message is used in the neuromuscular junction?

Answer 2

A chemical message.

Question 3

What sort of gates are located on the presynaptic membrane?

Answer 3

Voltage gated Ca++.

Question 4

What sort of synapse uses ACh (acetylcholine)?

Answer 4

Cholinergic.

Question 5

What is the axon hillock?

Answer 5

The hillock is the place on the nerve that decides whether or not to send the AP.

Question 6

What is the effect of APs traveling back up the neuron?

Answer 6

It can affect plasticity.

Question 7

What is an axosomatic synapse?

Answer 7

A synapse on the body of a nerve cell.

Question 8

What is an axodendritic synapse? How many types?

Answer 8

A synapse on the dendrite of a cell. Two types: 1) spine and 2) shaft.

Question 9

What is an axo-axonic synapse?

Answer 9

When the synapse is right on the bouton.

Question 10

What is a quantal content? What is the average in the NMJ as compared to CNS?

Answer 10

of quanta released per AP. NMJ avg. 40-80. CNS is much lower.

Question 11

What is post-tetanic potentiation/depression?

Answer 11

Several seconds after many, rapid APs are fired, you fire another one and the AP can be increased (potentiation) or reduced (depression).

Question 12

What is low-frequency depression?

Answer 12

Slow, repetitive action in a pathway that results in an AP of diminishing magnitude. Habituation.

Question 13

What is a retrograde chemical messenger?

Answer 13

A post-synpase releases a messenger that increases the production of the pre-synaptic neuron. This could be nitric oxide.

Question 14

What is homologous desensitization for a GCPR?

Answer 14

GPCR kinase (GRK) phosphorylates GPCR, this recruits arrestin, GPCR is endocytosed and either degraded or recycled.

Question 15

What is heterologous desensitization for a GPCR?

Answer 15

Repeated stimulation that leads to a desensitivity.

Question 16

What does a competitive antagonist do to Vmax and Km?

Answer 16

Vmax is the same.

Km is increased.

Question 17

What does a noncompetitive antagonist do to Vmax and Km?

Answer 17

Vmax is decreased. Km is the same.

Question 18

What is an agonist, antagonist and inverse agonist?

Answer 18

Agonist: response
Antagonist: no response
Inverse Agonist: decreased response

Question 19

What does Ga-S do?

Answer 19

activates cAMP

Question 20

What does Ga-i do?

Answer 20

inhibits cAMP

Question 21

What does Ga-q do?

Answer 21

activates PLC-beta which increases DAG (activates PKC) and IP3 (increases intracellular Ca++)

Question 22

How does Gs regulate adenylyl cyclase?

Answer 22

Gs activates adenylyl cyclase which coverts ATP to cAMP which then activates PKA.

Question 23

How does rhodopsin work with a Ca++ receptor?

Answer 23

Rhodopsin has a Gprotein, it activates cGMP/PDE which makes cGMP and keeps the Ca++ channel open. This is darkness. The channel closes when there is light.

Question 24

What does DAG activate?

Answer 24

PKC

Question 25

What does IP3 activate?

Answer 25

Ca++ channels. It increase intracellular Ca.

Question 26

How does Gq affect DAG and IP3?

Answer 26

Gq activates PLC-b, converts PIP2 to DAG and IP3.

Question 27

How can a GPCR regulate cell growth, motility and proliferation?

Answer 27

GPCR activates PI-3K which activates TFs associated with cell growth, proliferation and motility.

Question 28

What is transautophosphorylation?

Answer 28

When RTK dimerizes they becomes active and cross-phosphorylate each other.

Question 29

What is a GEF?

Answer 29

Guanine Exchange Factor. Turns GDP into GTP and helps to activate RAS G protein.

Question 30

What is GAP?

Answer 30

GTPase Activating Protein. Helps RAS G proteins to turn GTP to GDP, thus inactivating the protein.

Question 31

What is RAS?

Answer 31

RAS is a small G protein. GEF helps to activate it and GAP helps to deactivate it. It is a monomeric protein.

Question 32

How does RTK make IP3?

Answer 32

RTK binds to SH2 which recruited PLC gamma. That turns PIP2 into DAG and IP3.

Question 33

What is the fxn of IP3?

Answer 33

IP3 opens channels to increase intracellular Ca++ levels.

Question 34

What is the primary excitatory transmitter in the CNS? Primary inhibitory?

Answer 34

Excite: Glutamate Inhibit: Gaba, Glycine

Question 35

How many keys does the NMDA need to be opened? What are they?

Answer 35

2. A voltage-gated channel and a glutamate gate.

Question 36

What are two ways to activate PI-3K?

Answer 36

RTK and beta/gamma subunits.