Brainscape's Knowledge GenomeTM

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


See full index

Physiology and Pharmacology > Membrane permeability > Flashcards

Membrane permeability Flashcards

1
Q

How permeable is the plasma membrane?

A

Semi-permeable

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

What types of molecules can pass across plasma membranes?

A

Hydrophobic molecules

Small uncharged polar molecules

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

What are some examples of hydrophobic molecules that pass across plasma membranes?

A

Oxygen

Carbon dioxide

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

What are some examples of small uncharged polar molecules that can pass across plasma membranes?

A

Water

Urea

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

What types of molecules cannot pass across plasma membranes?

A

Large uncharged polar molecules

Ions

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

What is an example of a large uncharged polar molecule that cannot pass across plasma membranes?

A

Glucose

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

What are the types of transport of molecules across plasma membranes?

A

Passive transport/active transport

Uniport/co-transport

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

What are the types of passive transport?

A

Simple diffusion

Facilitated diffusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is simple diffusion?

A

Molecule moving directly across plasma membrane down its concentration or electrical gradient

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

What shape does a graph of concentration/electrical gradient against rate of transport for simple diffusion look like?

A

Straight line

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

Is simple diffusion saturable?

A

No

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

What is facilitated diffusion?

A

Molecule moving across plasma membrane by transport protein down its concentration or electrical gradient

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

What are the types of transport proteins?

A

Carrier proteins

Channel proteins

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

How do carrier proteins transport molecules across the plasma membrane?

A

Ligand binds to protein
gives conformational change in protein
protein internalises ligand and releases it to other side of plasma membrane

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

What are the types of channel proteins?

A

Ligand-gated

Voltage-gated

Mechanically-gated

17
Q

How do ligand-gated channels transport molecules across the plasma membrane?

A

Ligand binds to channel
channel opens up or closes
molecules can only move through open channel to the other side of the plasma membrane

18
Q

How do voltage-gated channels transport molecules across the plasma membrane?

A

Changes in membrane potential
causes channel to open up
molecules move through it to the other side of the plasma membrane

19
Q

What is an advantage of channel proteins over carrier proteins?

A

Work faster because they can transport more molecules across plasma membrane in one go

20
Q

What determines the rate of passive transport?

A

How permeable the membrane is to the molecule, how many transporter proteins are present for that molecule

The difference in concentration on either side of the plasma membrane

22
Q

What does a graph of a concentration against rate of transport for facilitated diffusion look like?

A

Rectangular hyperbola

23
Q

What is Vmax?

A

The maximum transport rate in facilitated diffusion

24
Q

What is Km?

A

The concentration that gives half of Vmax in facilitated diffusion

25
Q

What is happening to the transporter proteins at Vmax?

A

They are all working as much as they can

cannot transport any more molecules any faster

26
Q

What is active transport?

A

Transports molecules against their electrical or concentration gradient
using energy from ATP hydrolysis

26
Q

What is deltaG for passive transport?

A

Negative

27
Q

What is deltaG for active transport?

A

Positive

28
Q

What determines whether a molecule is transported across a plasma membrane by passive or active transport?

A

Its concentration gradient

Its electrical gradient

29
Q

What is uniport?

A

Transporter moves one molecule across plasma membrane at a time

30
Q

What is co-transport?

A

Transporter moves two molecules across plasma membrane at a time

31
Q

What are the types of co-transport?

A

Symport

Antiport

33
Q

What is symport?

A

Transporter moves two molecules across plasma membrane in one direction at a time

34
Q

What is antiport?

A

Transporter moves two molecules across plasma membrane in opposite directions at a time

34
Q

What are the roles of transport of molecules across plasma membrane?

A

Maintaining ionic composition

Generating ion gradients for electrical excitability of nerves and muscle

Regulation of intracellular pH

Regulation of cell volume

Controlling concentrations of building blocks, fuels, waste products etc.

35
Q

How do mechanically-gated ion channels transport molecules across the plasma membrane?

A

Plasma membrane deformation
causes the channel to open up
molecules move through it to the other side of the plasma membrane

Physiology and Pharmacology (20 decks)

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