Diffusion

Question 1

What is the definition of diffusion?

Answer 1

The net movement of particles down a concentration gradient from a region of high concentration to low concentration

Question 2

Is diffusion an example of active or passive transport?

Answer 2

Passive

Question 3

What is passive transport?

Answer 3

Transport which doesn’t require energy in the form of ATP

Question 4

What two things affect diffusion across a membrane?

Answer 4

1. Surface area of the exhange surface
2. Thickness of the membrane which affects the distance that diffusion occurs across

Question 6

What type of molecules cannot diffuse across the phospholipid bilayer?

Answer 6

Hydrophyllic polar molecules and ions

Question 7

Give the two things which affect the rate of diffusion

Answer 7

1. Temperature
2. Concentration gradient

Question 8

Give the two things which affect the rate of diffusion across a membrane

Answer 8

1. Surface area of exchange surface
2. Thickness of membrane which affects the distance that diffusion occurs across

+ (in facilitaded diff. the number of channel proteins and carrier proteins)

Question 9

Name the two types of proteins involved in faciliated diffusion

Answer 9

1. Protein channels
2. Carrier proteins

Question 10

Describe how carrier proteins faciliate the diffusion of molecules/ions across a membrane in facilitated diffusion

Answer 10

1. The binding site in carrier proteins are specific to a particular molecule
2. When the molecule binds to the protein
3. The protein will change shape to allow the molecule through the membrane

Question 11

Describe how channel proteins faciliate the diffusion of molecules/ions across a membrane in facilitated diffusion

Answer 11

1. Channel proteins are specific to a particular molecule
2. They contain water which allows polar molecules to move through it

Question 12

Is facilliatated diffusion an active or passive process

Answer 12

Passive

always write this first in long descriptive answers ab/ facilitated diffusion/diffusion

Question 13

What is the rate of faciliated diffuion also dependant on that normal diffusion is not

Answer 13

The number of channel and carrier proteins in the phospholipid bilayer