1: Active Transport Flashcards

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

Define ‘active transport’.

A

the movement of substances across membranes using energy from ATP

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

What can active transport do that diffusion cannot?

A

move substances against the concentration gradient - from a region of lower concentration to a region of higher concentration

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

What are protein pumps in the membrane used for?

A

active transport

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

How many different substances can a protein pump transport? How, then, do cells control what is absorbed and what is expelled?

A
  • one substance only

- by changing the type of protein pump

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

How many different directions do protein pumps work? What does this mean for the substance?

A
  • one specific direction

- substance can only enter the pump on one side and only exit on the other side

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

Draw and label a diagram of a protein pump transporting a particle. (p12)

A
  1. particle enters the pump from the side with a lower concentration
  2. particle binds to a specific site. Other types of particle cannot bind.
  3. Energy from ATP is used to change the shape of the pump.
  4. Particle is released on the side with a higher concentration and the pump then returns to its original shape.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Where can sodium-potassium pumps be found? What do they do?

A
  • found in the axons of neurons

- moves sodium ions and potassium ions across the membrane

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

In a sodium-potassium pump: which direction are sodium and potassium ions pumped (relative to each other)? What, therefore, is the technical term for this sort of pump?

A
  • opposite directions

- an antiporter

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

How is the energy required for pumping sodium and potassium ions in a sodium-potassium pump obtained? What therefore is this type of reaction called?

A
  • by converting ATP –> ADP and phosphate

- an ATPase (or Na+/K+ -ATPase)

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

In a sodium-potassium pump, how much energy does one ATP provide?

A
  • enough energy to pump two potassium ions in and three sodium ions out of the cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does the pumping of potassium ions and sodium ions in a sodium-potassium pump achieve? Why is this necessary?

A
  • a concentration gradient between the inside and outside of the neuron
  • needed for the transmission of nerve impulses in axons
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is situated in the centre of a sodium-potassium pump?

A

5 binding sites:

  • 2 binding sites for K+ ions
  • 3 binding sites for Na+ ions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How many states does a sodium-potassium pump have? How does the sodium-potassium pump change states?

A
  • two alternate states

- using energy from ATP

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

Describe the two alternate states in a sodium-potassium pump.

A

in one:

  • access to binding sites from outer side of membrane
  • stronger attraction to K+ ions, so Na+ ions are discharged from the cell an K+ ions bind.

in the other:

  • access to binding sites from the inside of membrane
  • stronger attraction to Na+ ions, K+ ions discharged
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does fluidity of membranes allow them to do?

A

move and change shape

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

Outline endocytosis?

A

small piece of the plasma membrane can be pinched off to create a vesicle containing some material from outside the cell

17
Q

What is the opposite of endocytosis? Outline the opposite of endocytosis.

A
  • exocytosis

- vesicles move to the plasma membrane and fuse with it, releasing the contents of the vesicle outside the cell

18
Q

What are vesicles in a cell used for? Give an example.

A
  • used to move materials from one part of the cell to another
  • vesicles move proteins from the RER to the Golgi apparatus
19
Q

Draw a diagram showing the process of endocytosis. (p12)

A

-

20
Q

Draw a diagram showing the process of exocytosis. (p12)

A

-

21
Q

Draw a diagram showing the process of vesicles transporting proteins in a cell. (p12)

A

-