Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

3. ICPP > 3.1 Membrane Permeability > Flashcards

3.1 Membrane Permeability Flashcards

1
Q

What is a semi-permeable membrane?

A

A layer through which only allowed substances can pass.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the permeability coefficient? What does it depend on?

A

Measure of time taken to pass through the membrane
E.g. H2O 10^-2 (very quick), Na+ 10^-14 (very slow)

Depends on what membrane you are measuring for e.g. Erythrocyte vs axon.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Give some examples of roles of transport

A
  1. Maintain ionic concentration
  2. Maintain intracellular pH
  3. Regulate cell volume
  4. Concentration metabolic fuels/building blocks
  5. Concentration products/toxins
  6. Generation of ion gradients = needed for electrical excitability
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a ping-pong transport protein?

A

Moves one molecule per protein at any one time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How does a channel by facilitated diffusion work?

A
  1. High conc to low conc
  2. Carrier protein (gate fully opens allows lots of moles through)
  3. Passive (no energy required)
  4. Large and charged molecules (glucose, ions)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is simple diffusion?

A
  1. Movement from high conc to low conc gradient
  2. No carrier protein
  3. Passive (no energy)
  4. Very small (O2) and lipid soluble molecules (Steroids)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does an ion channel by facilitated diffusion work?

A
  1. Ligand gated
    - high conc to low conc
    - carrier proteins
    - Ligand binds, channel opens/closes and ions go through
  2. Voltage gated
    - membrane depolarisation (one side more positive than other) causes channel to open
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is active transport?

A
  1. Transport of ions/mols against unfavourable concentration/electrical gradient
  2. Energy required
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is passive transport?

A
  1. Occurs spontaneously either through lipid bilayer/proteins along concentration gradient
  2. No energy required
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Intracellular and extracellular values of Chlorine?

A

Intra - 4.2mM

Extra - 123mM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Intracellular and extracellular values of sodium?

A

Intra - 12mM

Extra - 145mM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Intracellular and extracellular values of Calcium?

A

Intra - 10^-7M

Extra - 1.0-1.5mM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Intracellular and extracellular values of potassium?

A

Intra - 155mM

Extra - 4mM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the difference between primary and secondary active transport?

A

Primary - Energy derived directly from breakdown of ATP
Secondary - Energy derived secondarily from energy that has been stored in the form of an ionic concentration difference between two sides of the membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the difference between uni transport and co transport?

A
  1. Uniport - Only one mol transported at a time
    E.g proton pump in mitochondria
  2. Co transport
    - Symport - 2 solutes moving in same direction
    - antiport - 2 solutes moving in opposite directions
    E.g. Na+/glucose cotransporter - 2 sodiums and 1 glucose move into cytoplasmic space
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the osmosis?

A

Movement of water across semi permeable membrane from region of low solute concentration to region of higher solute concentration ‘
Passive transport
No energy required

17
Q

What is Ca2+ ATPase and its function?

A
  1. Primary active transport
  2. UNIPORT
  3. Exclude Ca2+ ions
  4. Requires ATP
  5. High affinity, low capacity
18
Q

What is Na+ Ca2+ exchanger

A
  1. Secondary active transport (as driven by extracellular Na+ conc)
  2. ANTIPORT (cotransport)
  3. 3Na+ in, 1 Ca2+ out
  4. Low affinity, high capacity
19
Q

What is the sodium pump and its function?

A
  1. Na+ K+ ATPase
  2. Active transport as uses ATP
  3. Antiport
  4. 3 Na+ out and 2K+ in maintaining normal concentration gradient
  5. High K+ inside as responsible for resting membrane potential (-70mV)
20
Q

Na+H+ exchanger and its function?

A
  2. ANTIPORT
  3. 3 Na+ pump out from Na+K+ATPase, one Na+ pumped back in through Na+H+ exchanger, pumping out one H+ too.
21
Q

Na+Glucose co-transport and its function?

A
  1. Entry of two Na+ provides energy for entry of 1 glucose molecules against concentration gradient
  2. Symport - co transport
  3. E.g. Small intestine/kidney
22
Q

F1F0 ATPase and function?

A

Active transport in reverse mode

Generates ATP in cell

23
Q

What is an aqua porin?

A

Water channel

24
Q

Give two clinical examples where there is a problem with a pump?

A

In cystic fibrosis patients, CFTR not present in apical membrane of epithelial cells.
Therefore chloride ion transport across membrane compromised
Water does not follow to hydrate secreted mucus causing it to become viscous and cause infection

Vibrio Cholera
Protein Kinase A effects CFTR 
Too much chlorine leaves
Too much water follows out
Causes diarrhoea and dehydration
25
Q

Give an example of a drug effecting

A
  1. Fluoxetine (antidepressant)
  2. Outward flow of K+ down concentration gradient
  3. Leads to uptake of serotonin in presynaptic cleft and by platelets with Na+ ion
  4. Fluoxetine inhibits SERT (serotonin reuptake transporter) so NT stays in cleft for longer!

3. ICPP (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions