Exam 2 Part 2

Question 1

plants, fungi, and bacteria gradient

Answer 1

use proton pumps to use a proton gradient while animal cells use the sodium gradient

Question 2

ion channels

Answer 2

can open and close
are selective
conformation changes for opening but no conformation change to select things through
R groups on the amino acids allow for selectivity

Question 3

regulation of ion channel opening and closing

Answer 3

voltage-gated
ligand gated (extracellular ligand)
ligand-gated (intracellular ligand)
mechanically-gated

Question 4

voltage gated channels

Answer 4

changes in polarity opens and closes

Question 5

ligand gated channels -extracellular

Answer 5

ligand outside cell binds and opens
capsasm
seratonin

Question 6

ligand gated channels -intracellular

Answer 6

internal signal binds and opens

Question 7

mechanically gated channels

Answer 7

mechanical stimuli

hearing, pressure

Question 8

how to measure ion channel function

Answer 8

through current using patch clamping
analyze very small portion of cells
detatch patch of membrane and place in a charged pool, then measure ions

Question 9

membrane potential

Answer 9

balance of + and - charges on the faces of the membrane

Question 10

events for depolarization

Answer 10

1. ligand binding/mech. stimuli/auto stimuli
2. opening of an ion channel
3. voltage gated Na+ channel

Question 11

voltage gated Na+ channels

Answer 11

open/close depending on the membrane potential
-another ion channel needs to have opened (usually ligand gated)
automatically inactivates itself so that cell can repolarize

Question 12

recovery and membrane repolarization

Answer 12

use Na+/K+ pump to reestablish membrane potential

Question 13

refractory period

Answer 13

time when Na+ gate is inactivated and neuron cannot fire

Question 14

propagation of signal

Answer 14

needs a stimulant
coordination of channels
signal moves down the axon and in only 1 direction because channels close

Question 15

what happens when an action potential reaches a nerve terminal

Answer 15

electrical signal moves down activated terminal, Ca++ channel opens.

2. Ca++ stimulates synaptic vesicles to fuse with plasma membrane
3. vesicles release their neurotransmitter into the synaptic cleft (exocytosis)

Question 16

when neurotransmitter reaches postsynaptic cell

Answer 16

the released neurotransmitter binds to a transmitter-gated ion channel in the postsynaptic cell
2. the ion flow alters the membrane potential of the cell and converts the chemical signal to an electrical one

Question 17

synaptic signalling importance

Answer 17

enables us to think, act, learn, and remember. has to do with the connectivity of the brain