B1

Question 1

What is diffusion?

Answer 1

The net movement of particles from an area of higher concentration to an area of lower concentration.

Question 2

What substances can diffusion occur for?

Answer 2

Water and gas

Question 3

What are the three factors that affect the rate of diffusion?

Answer 3

• Concentration gradient
• Temperature
• Surface area: larger surface area=higher rate of diffusion

Question 4

Define osmosis:

Answer 4

diffusion of water molecules
net movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration

Question 5

Define active transport:

Answer 5

Movement of molecules against their concentration gradient using energy from the cell across a membrane
requires special proteins to transfer the molecules from one side to the other