Diffusion Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Define diffusion

A

the net movement of particles down a concentration gradient from an area of higher concentration to an area of lower concentration until equilibrium is reached.

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

What is facilitated diffusion?

A

Large, polar molecules and charged ions can only enter the cell with the aid of proteins.

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

What is simple diffusion?

A

Lipid soluble molecules and very small molecules such as oxygen and carbon dioxide can diffuse directly through the lipid bilayer.

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

How do carrier proteins work?

A
  • have a specific shape that match the shape of the molecule to be transported
  • the molecule or ion binds to this site snd the protein changes shape.
  • this moves the substance across the membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How do channel proteins work?

A
  • have water filled pores that span the membrane.
  • each has a specific shape through which a particular molecule or ion can pass.

(some are gated and can be open or closed)

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

When does the rate of uptake increase in simple diffusion?

A
  • When the concentration of the substance outside of the cell increases because there is a bigger concentration gradient.
  • When the temperature increases because the molecules/ions have more kinetic energy therefore move faster.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

When does the rate of uptake change in facilitated diffusion?

A
  • levels off at high concentrations because the carrier/channel proteins are becoming saturates with molecules/ions
  • at high temperatures, the rate of uptake may change because the carrier/channel proteins have denatured.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Why is diffusion called ‘passive transport’?

A
  • doesn’t require ATP

- moves down a concentration gradient.

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