Brainscape's Knowledge GenomeTM

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


See full index

ESA1 - Physiology and Pharmacology > Membrane Permeability > Flashcards

Membrane Permeability Flashcards

1
Q

Define membrane permeability

A

The ability of a membrane to allow molecules to pass through

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

What is passive diffusion?

A

Molecules move from an area of high concentration to an area of low concentration without using energy

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

What is facilitated transport?

A

The usage of channels to transport molecules or ions across a membrane without the use of energy

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

What is active transport?

A

The movement of molecules or ions from an area of low concentration to an area of high concentration with the use of energy

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

What is a semi-permeable membrane?

A

A layer through which only certain substances are allowed to pass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which class of molecules are lipid bilayer most permeable to?

A

Hydrophobic molecules (eg oxygen, carbon dioxide, nitrogen and benzene)

Small uncharged polar molecules (eg water, urea, glycerol)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What do permeability coefficients tell us?

A

Higher permeability coefficient - higher permeability

Cm/s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is passive transport dependent on?

A

Permeability and concentration gradient

Rate of transport increases linearly with increasing concentration gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are transport processes important for?

A
  • Maintenance of ionic composition
  • Maintenance of intracellular pH (movement of H+)
  • Regulation of cell volume
  • Concentration of metabolic fuels and building blocks
  • The expulsion of metabolic waste products and toxic substances (eg urea)
  • The generation of ion gradients necessary for the electrical excitability of nerve and muscle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the accepted model of membrane transport proteins?

A

‘Ping-pong transport’

Molecule binds, protein internalises, conformational change

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

If /\G is positive/negative what does this mean?

A 
Positive = active transport
Negative = passive transport
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Where is the energy that is required in active transport taken from?

A

Hydrolysis of ATP

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

What is the approximate value of intracellular ca2+?

A

10^-7 M

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

What is the approximate value of extracellular ca2+?

A

1.0 - 1.5 mM

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

What is the approximate value of intracellular Cl-?

A

4.2mM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the approximate value of extracellular Cl-?

A

123 mM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the approximate value of intracellular K+?

A

155mM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the approximate value of extracellular K+?

A

4mM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the approximate value of intracellular Na+?

A

12mM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the approximate value of extracellular Na+?

A

~145mM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is Ca2+ ATPase an example of?

A

Primary active transporter (uses ATP)

22
Q

What is uni-transport?

A

Only one molecule transported at a time

23
Q

What is symport?

A

Two molecules are transported at the same time in the same direction

24
Q

What is anti port?

A

Two molecules are transported at the same time in opposite directions

25
Q

How many Na+ ions are pumped out of the cell compared to K+ ions?

A

3 Na+ out

2 K+ in

26
Q

What do the alpha and beta subunits of the sodium pump do?

A

Alpha unit - K+, Na+, ATP binding sites

Beta unit - glycoproteins directs pump to cell surface

27
Q

What is mainly responsible for the resting membrane potential being -70mV?

A

K+ diffusion through channels

28
Q

What is the primary active transporter associated with Ca2+?

A

Ca2+ Mg2+ ATPase (uses ATP)

Uniport

29
Q

What is the secondary transporter associated with Ca2+?

A

Na2+ Ca2+ exchanger (NCX)

No ATP used

Antiport

30
Q

Explain the Na+ Ca2+ exchange

A

Inwards flow of Na+ ions down the Na+ concentration gradient drives the outward flow of Ca2+ up its concentration gradient (antiport)

31
Q

Explain the Na+ H+ exchange

A

Inward flow of Na+ down its concentration gradient leads to cell alkalinisation by removing H+ (antiport)

32
Q

Explain Na+ glucose co transport (small intestine and kidney)

A

Entry of 2 Na+ ions provides the energy for the entry of 1 glucose molecule against its concentration gradient (symport)

33
Q

What percentage of basal metabolic rate is used to keep the sodium pump working?

A

25%

34
Q

Why is the sodium pump called a P-type ATPase

A

ATP phosphorylates aspartate, producing a phosphoenzyme intermediate

35
Q

Which subunit of the sodium pump directs pump to cell surface?

A

Beta subunit

36
Q

What creates the high intracellular concentration of potassium?

A

Sodium pump

37
Q

What is NCX driven by?

A

Na+ concentration outside the cell, not ATP

38
Q

Describe the Na+-glucose co transport system

A

Entry of 2Na+ provides the energy for the entry of 1 glucose molecule against its concentration gradient (symport)

39
Q

What does Fluoxetine inhibit?

A

Serotonin Reuptake Transporter (SERT)

40
Q

Which types of molecules can pass through the lipid bilayer?

A

Hydrophobic molecules eg O2, CO2, N2, Benzene

Small, uncharged polar molecules eg H20, urea, glycerol

41
Q

Which types of molecules cannot pass through the lipid bilayer?

A

Large uncharged polar molecules eg glucose and sucrose

Ions eg Na+, K+, H+, Ca2+, Cl-

42
Q

How much more is the extracellular calcium ion concentration compared to intracellular?

A

10,000 times more

43
Q

What is an example of active transport in reverse mode?

A

ATP synthase

44
Q

What is uniport?

A

Involves the movement of one type of molecule or ion across the membrane

45
Q

What is an example of uniport?

A

GLUT1 glucose carrier

46
Q

What is symport?

A

Involves the movement of two or more different molecules or ions across a phospholipid membrane in the SAME direction

47
Q

What is an example of symport?

A

Na+/glucose cotransporter - 2Na+ and 1 glucose

48
Q

What is antiport?

A

Involves the movement of of two or more different molecules or ions across a phospholipid membrane in OPPOSITE directions

49
Q

What is an example of antiport?

A

NCX - 1Ca2+ for 3Na+

50
Q

Which type of transport is shown by the Na+-H+-Exchanger?

A

Antiport

ESA1 - Physiology and Pharmacology (11 decks)

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