End Of Unit Questions

Question 1

Give an example of when active transport is carried out by cells

Answer 1

Active transport is used by plant roots to absorb mineral ions

Question 2

What is meant by against a concentration gradient?

Answer 2

Particles move from a lower concentration to a region of a higher concentration

Question 3

Name the exchange surfaces in the lungs and intestines

Answer 3

Lungs: alveoli

Small intestine: villi

Question 4

What are the features of an efficient exchange surface?

Answer 4

• large surface area
• thin walls
• good blood supply

Question 5

Describe the process involved in breathing in

Answer 5

The rib muscles and the diaphragm contract so the volume inside the chest increases so the pressure decreases so air is forced into the lungs

Question 6

Which sorts of patients benefit from an iron lung machine?

Answer 6

Patients who are paralysed and cannot breathe for themselves

Question 7

How is the surface area of a root increased and why is this important?

Answer 7

By the root cells which have projections called root hairs to absorb mineral ions and water from the soil

Question 8

Why is the rate of transpiration higher on a bright day?

Answer 8

The plant is photosynthesising at a faster rate due to more light energy, so needs to take in more carbon dioxide, so the stomata will be open as wide as possible

Question 9

On humid days, the rate of transpiration is slow even when it is hot, explain why.

Answer 9

The air already contains lots of water as it is humid, this means the concentration gradient is not very steep so the transpiration is greatly reduced

Question 10

In what way is osmosis different to diffusion?

Answer 10

Osmosis only refers to the diffusion of water