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BIOL 2202 CMBean Midterm 2 > Chapter 12 > Flashcards

Chapter 12 Flashcards

1
Q

which molecules can pass thru the lipid bilayer via simple diffusion (order)

A

can pass thru (hydrophobic)
-non polar molecules (O2,CO2,steroid, hormones)

only partially (hydrophilic)
-small uncharged polar molecules (water,ethanol)

then
-large uncharged polar molecules (amino acids,glucose)

cannot pass thru (hydrophilic ions)
-charged molecules

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2
Q

which would diffuse across a cell membrane most easily

A

small, uncharged, non polar molecules

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3
Q

water can form a ____charge around ions

A

hydration charge

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4
Q

where are the higher levels of Ca+ in the cell

A

higher outside cell (ECF)

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5
Q

where are the higher levels of H+ in the cell

A

higher inside cell (ICF)

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6
Q

where are the higher levels of K+ in the cell

A

higher inside the cell (ICF)

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7
Q

where are the higher levels of Na+ in the cell

A

higher outside the cell (ECF)

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8
Q

using the sodium potassium pump which way do Na and K move

A

3 Na+ out

2 K+ in

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9
Q

what are the charges inside vs outside the cell and which way do molecules want to move

A

(-) inside
(+) outside

  • want to move from (+) to (-)
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10
Q

what is passive transport and the two types

A
  • no ATP required
  • moves along concentration gradient

2 types:
simple diffusion & facilitated diffusion

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11
Q

what is simple diffusion

A
  • no proteins
  • no ATP
  • conc gradient
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12
Q

what are the two types of facilitated diffusion

A

transporters & channel proteins

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13
Q

describe transporter facilitated diffusion

A
  • binds solute one side of the membrane and changes conformation to transport solute to other side of membrane (specific shape to accept)
  • slower rate than channel
  • specifically glucose transporters
  • can move in either direction
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14
Q

describe channel facilitated diffusion

A
  • usually transport of ions
  • gated / ungated
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15
Q

what are the types of gated channel facilitated diffusion

A
  • voltage gated (energy/ voltage)
  • mechanically gated (pressure/touch)
  • ligand gated (neurotransmitters)
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16
Q

what is active transport and the 3 types

A

ATP is required

-secondary
-primary
-light driven

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17
Q

describe light driven active transport

A

bacteriorhodopsin-proton pump

18
Q

describe primary active transport with an example

A

ex. Na+/K+ pump

  • 3 Na out and 2 K into cell
  • both are moving AGAINST concentration gradient
  • energy is needed for this by direct ATP hydrolysis
19
Q

in many cells Na/K pump generates the ________

A

resting membrane potential

20
Q

describe secondary active transport

A
  • coupled transport of two solutes! (symport & antiport)
  • has a driving ion used to drive uphill transport of a second solute
  • uses an already established gradient
21
Q

what is symport vs antiport

A

symport - both going same ways
antiport - going opposite ways

22
Q

how specifically in secondary active transport is there transport of two solutes

A

-ATP powered pump transports one solute to build up the electrochemical gradient

  • this gradient drives transport of second solute via a !different! channel or transporter
23
Q

3 types of transporters involved in transport of glucose

A
  1. Na/K pump
  2. Na driven glucose symport
  3. passive glucose transporter
24
Q

ion channels have ___ diversity

A

lots of

25
Q

pores are ____ selective and often ____

A

highly selective and often gated

26
Q

what can trigger the opening/closing of a channel and channels are highly ____

A
  • ligand binding
  • mechanical stimuli
  • voltage change

highly selective

27
Q

what are voltage gated channels important for and why

A

excitable cells
- because they open/ close in response to the membrane potential and reaching a particular threshold triggers channels to open

28
Q

what is the voltage of the threshold and resting membrane potential

A

RMP = -70mv
Threshold = -55mv

29
Q

describe the resting membrane potential (RMP)

A

= -70
- voltage gates closed
- potassium ion (K) ESTABLISHES resting membrane potential
- Na/K pump MAINTAINS -70

30
Q

what must first be produced before an action potential can be

A

graded potentials
- depolarize the cell to threshold and if threshold is reached causes an action potential
- are ligand gated

31
Q

will a stronger stimulus cause a larger action potential ? why

A

NO because it’s an all or nothing response

32
Q

once the stimulus reaches the threshold (-55mv) what happens

A

-opening of voltage gates

depolarizing
1. sodium comes into the cell FIRST and reaches 30 mv where the Na voltage gates close and inactivate

repolarizing
2. potassium (K) goes out of the cell and K voltage gates open

hyperpolarizing
- K gates still open / Na gates close
- Na/K pump moves hyperpolarization back to RMP

33
Q

describe absolute refractory period vs relative refractory period

A

absolute RP (de & repolarizing phases)
- voltage gated sodium (Na) channels OPEN
- neuron cannot generate another AP

relative RP (hyperpolarizing phase)
- voltage gated sodium (Na) channels CLOSED
- second AP can only occur with a larger than normal stimulus

34
Q

how do action potentials propagate

A

by depolarizing the section of membrane directly adjacent to it and as this spread along each section then undergoes repolarization after

35
Q

what part of neuron receives the stimulus ?

A

dendrites

36
Q

how is an impulse transmitted from one neuron to another (4)

A
  1. AP travels along presynaptic neuron and arrives at axon end terminal
    •voltage gated calcium channels open
    •calcium rushes in
    •neurotransmitter vesicles mobilize
  2. neurotransmitter vesicles fuse with membrane
  3. at membrane release neurotransmitters that diffuse across the synaptic cleft
  4. neurotransmitters bind to ligand gated sodium (Na) channels on post synaptic cleft causing them to open and Na rushes in
    (causes a graded potential that could reach threshold and cause an AP / repeat whole process over again)
37
Q

what is the synaptic cleft

A

gap between pre and post synaptic cells

38
Q

what is the synapse

A

site of communication between two neurons

39
Q

what and EPSPs and IPSPs

A

EPSPs
(excitatory post synaptic potential)
= depolarizing - increase chance that neuron will fire an AP

IPSPs
(inhibitory post synaptic potential)
= hyperpolarizing- decrease chance that neuron will fire an AP / more K going out

40
Q

is the opening of K channels caused by the closure of Na channels ?

A

NO
- when threshold is reached they both open K channels are just slower so happen second

41
Q

what do inactivation gates do ?

A
  • on sodium gated channels
  • play an important role in refractory period
  • prevents AP from moving backwards
42
Q

how can you view channels opening and closing ?

A

using patch clamp recording

BIOL 2202 CMBean Midterm 2 (4 decks)

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