Membrane transport

Question 1

Why is membrane transport important?

Answer 1

Protects metabolic reactions within cell, Communicates and exchanges materials between cell=environment, transport proteins in cell membrane allow for controlled interaction

Question 2

Membrane permeability

Answer 2

• High permeability for small hydrophobic molecules and gases
• Limited permeability for water
• Very low permeability for ions and large solutes

Question 3

Transport proteins

Answer 3

• Create a hydrophilic passage
• Create a filter
• Provide possibility for energy coupling
• provide possibility for regulation

Question 4

Facilitated diffusion

Answer 4

• Transport proteins create a hydrophilic pore
• Molecules diffuse through this pore

Question 5

What are two forces that drive the movement of molecules across membranes?

Answer 5

Chemical gradient and Electrical gradient

Question 6

Chemical gradient

Answer 6

Concentration gradient

Question 7

Electrical gradient

Answer 7

Charge gradient (Only relevant for charged molecules (ions) )

Question 8

The electrochemical gradient

Answer 8

The net driving force for the movement of a molecule resulting from the combination of the chemical and electrical gradient

Question 9

Active transport

Answer 9

Moves substances against the electrochemical gradient. Requires input of energy.

Question 10

What are the transport proteins for active transport?

Answer 10

Pumps and co-transport systems

Question 11

Passive transport

Answer 11

Moves substances down the electrochemical gradient. Requires no input of energy.

Question 12

What are the transport proteins for passive transport?

Answer 12

Channels and carriers

Question 13

What do pumps establish?

Answer 13

Electrochemical gradients

Question 14

What do electrochemical gradients drive?

Answer 14

The active transport of other solutes through co-transport systems
The passive transport of solutes through channels and carriers