01 | Introduction Flashcards Preview

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Flashcards in 01 | Introduction Deck (25):
1

What can be used as a measure of neuron activity?

Rate of ATP synthesis by mitochondria in neuron

2

What are STORAGE GRANULES?

Holds vesicles at the presynaptic membrane

3

RMP for normal human neurons is around...(value)

-70 mV

4

How thick is the cell membrane? (value)

6 nm

5

When ions pass through passively, they use __. When actively, they use __.

1. Ion channels
2. Transport molecules (pumps, transporters)

6

3 components of an ion channel

1. Pore
2. Selectivity filter
3. Channel gate

7

__ channel has increased probability of being open. ___ channel has decreased probability of being open.

1. Activated
2. Deactivated

8

Define: inactivation

(@ electrical synapses) conformational change prevents channel from opening, even if there is a stimulus

9

Define: desensitization

(@ chemical synapses) conformational change prevents channel from opening, even if there is a stimulus

10

Define: open channel block

something is physically occluding the pore

11

Explain voltage clamp

The voltage clamp is an experimental method to measure the ion currents while holding the membrane voltage at a set level.

12

Whole cell patch clamp

- Mimic real cell
- Change intracellular concentrations

13

Outside out patch clamp

- isolate channels
- change extracellular conc.

14

Inside-out patch clamp

- Isolate channels
- Change intracellular concentrations
- Example receptors activated by intracellular ligands

15

How many subunits does nAChR have? List them. What are the requirements?

5 subunits (α, β, γ, δ) that come together -- any combination, but has to have at least 2 α (this becomes the ligand binding site)

16

How many times does each subunit in nAChR cross the membrane? Which segment forms the pore?

4 times (M1-4)
M2 forms pore

17

How does pore open on nAChR?

M helices rotate toward channel wall

18

What are the 3 voltage-gated channels with similar morphologies? What is that morphology?

- Na, Ca, K
- 4 α subunits with 5 TM regions in each subunit (S1-6)
- 3rd residue of S4 is positive

19

What does the positive residue in voltage-gated channels do?

- Voltage sensor
- Couples voltage changes in the membrane to channel opening mechanisms

20

What are the additional subunits on Na channels? What are they used for?

2 TM β
- Activation and gating

21

Subunits of v-gated Ca channel

4 α1 subunits

22

What are the additional subunits on v-gated Ca channels? What are they used for?

Intracellular β, TM δ, extracellular α2
- Activation and gating

23

How does the AA sequence of v-gated K channels compare to other v-gated ion channels?

v-gated K channels have shorter AA sequence

24

What are the additional subunits on v-gated K channels? What are they used for?

Intracellular β + first few residues from N-terminal form the ball-and-chain inactivation gate

25

Which TM segments on v-gated K channels form the pore (P-loop)?

S5-6