Diffusion

Question 1

What is diffusion ?

Answer 1

Diffusion is the ( Net movement ) spread of particles from area of high concentration to an area of lower concentration

Question 2

Where does diffusion occur ?

Answer 2

In both solutions and gases - particles in these substances are free to move about freely.
The simplest type is when different gases diffuse through each other - example : smell of perfume diffuses through the air in the room

Question 3

What gives a faster diffusion rate ?

Answer 3

• bigger the concentration gradient, the faster diffusion rate
• Higher temperature = the faster diffusion rate because particles have more energy to move faster.
• Larger SA of membrane, faster diffusion rate as more particles pass through at once

Question 4

Use of cell membranes

Answer 4

They hold the cell together but let stuff in and out as well.
Dissolved substance can move in and out cells by diffusion, only very small molecules can diffuse through cell membranes like oxygen, glucose, amino acids and water.
Big molecules like starch and proteins can’t fit through membranes.

Question 5

What do particles flow through ?

Answer 5

Particles flow through cell membrane from where there’s high concentration to where there’s lower concentration.
They’re moving about randomly so they can go both ways - but if there are a lot more particles on one side of the membrane, there’s a net movement from that side.