N5S3 - Diffusion - 1.3

Question 1

Define Diffusion

Answer 1

Diffusion is the net movement of particles from an area of higher concentration to an area of lower concentration DOWN the concentration gradient

Question 2

Define the meaning of “Net Movement”?

Answer 2

It means the movement of all of the particles considered together as a group.

Question 3

Why is the cell membrane is known as “selectively permeable”?

Answer 3

Because only certain molecules can diffuse through them

Question 4

Define the term “Concentration Gradient”

Answer 4

It is the difference in the concentration between two areas of a substance

Question 5

Explain why diffusion important to all cells

Answer 5

It helps cells gain materials that are essential for energy and growth whilst also getting rid of waste products.

Question 6

Diffusion stops when…

Answer 6

…the concentration of the substance is equal in all areas.

Question 7

State three waste products a cell produces

Answer 7

• Carbon Dioxide - Waste product of Aerobic Respiration
• Urea
• Ammonia

Question 8

State three important substances a cell requires and describe their functions

Answer 8

• Glucose - Needed for Aerobic Respiration
• Oxygen - Needed as an energy source for making ATP
• Amino Acids - Needed for making Proteins

Question 9

State and describe the three factors that affect the rate of diffusion

Answer 9

1. Concentration Gradient - the larger the concentration gradient, the higher the rate of diffusion
2. Temperature - The higher the temperature, the higher the rate of diffusion
3. Surface Area - the larger the surface area, the higher the rate of diffusion.

Question 10

Explain the process of Diffusion

Answer 10

The particles collide with each other or their container, which makes them change direction. Eventually, the particles are spread through the whole container or substance.