Week 5 - Channel Physiology - Fitzakerly Flashcards Preview

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Flashcards in Week 5 - Channel Physiology - Fitzakerly Deck (8)
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1
Q

Do all channels have selectivity, gating and inactivation mechanisms?

A

ALL channels have selectivity and gating

ONLY SOME channels have inactivation

2
Q

List key differences between ion channel and transporters:

A

Ion channels:
passive, direct connection between intra and extra cellular space, only move ions, VERY fast

Transporters:
Passive or active, with or without concentration gradient, never have a direct connection between inside and outside, move small ions or larger molecules, not as fast as ion channels

3
Q

A cell with no aquaporins is places if a hypo tonic solution. What happens?

A

Nothing. NO lysis if no aquaporins present for osmosis.

4
Q

What are the 4 types of channel gating?

A

Leak: Always open (neurons)
Mechanical: (sensory)
Ligand: (Bound chemical changes conformation of channel)
Voltage-gated: In excitable cells

5
Q

Why would it be unlikely for both Na and Cl to pass through the same channel?

A

Generally channels are either all cation, all anion, or one specific ion, NOT an anion and a cation

6
Q

List 4 ways that an ion channel can open

A

membrane stretch
depolarization
ligand binding
random changes in position of channel gate

7
Q

Are ions more likely to leave or enter a cell through a channel?

A

Neither. They are bidirectional so it all depends on concentration and electrical gradients.

8
Q

Rank the 4 major ions in order of extracellular ion concentrations:

K, Na, Cl, Ca

A

Na+ > Cl- > K+ > Ca2+

Lots of Na outside the cell, Cl is inbetween, K+ most abundant intracellular ion, Ca is the least abundant intra and extracellularly