Diffusion

Question 1

Particles move about ____, but after a bit they end up ____ ____

Answer 1

Particles move about randomly, but after a bit they end up evenly spaced

Question 2

Define ‘diffusion’

Answer 2

The gradual movement of particles from an area of high concentrated to an area of low concentrated until they are equal

Question 3

What substance/s does diffusion happen in?

Why?

Answer 3

Solutions (liquids) and gases

The particles in these substances are free to move about randomly

Question 4

What is the simplest kind of diffusion?

Give an example

Answer 4

When different gases diffuse through each other

E.g. When the smell of perfume diffuses through the air in a room

Question 5

The bigger the difference in concentration, the ____ the diffusion rate

Answer 5

The bigger the difference in concentration, the faster the diffusion rate

Question 6

What is so ‘clever’ about cell membranes?

Answer 6

They hold the cell together, but they also let substances in and out of the cell

Question 7

How can dissolved substances move in and out of cells?

Answer 7

By diffusion

Question 8

What must a molecule be to be able to diffuse through cell membranes?

Answer 8

Very small

Question 9

Give 4 examples of molecules small enough to diffuse through cell membranes (+ 1 reason why)

Answer 9

1. Oxygen for respiration
2. Glucose
3. Amino acids
4. Water

Question 10

Name 2 molecules that are too big to fit through a cell membrane

Answer 10

1. Starch
2. Proteins

Question 11

Particles are moving about randomly, so they do go ____ ____ through a membrane.

However, if there is a high concentration of particles on one side of a membrane, there will be a ____ ____ from that side.

Answer 11

Particles are moving about randomly, so they do go both ways through a membrane.

However, if there is a high concentration of particles on one side of a membrane, there will be a net movement from that side.