PPQ's

Question 1

Tubifex worms are small, thin animals that live in water. They have no specialised gas exchange or circulatory system. The figure below shows a tubifex worm.
Name the process by which oxygen reaches the cells inside the body of a tubifex worm. (1)

Answer 1

Osmosis

Question 2

Define diffusion. (1)

Answer 2

Movement of molecules or ions from a region of higher concentration to a region of lower concentration.

Question 3

Define osmosis. (1)

Answer 3

Movement of water molecules across a selectively permeable membrane, from a region of higher water potential to a region of lower water potential.

Question 4

Define active transport. (1)

Answer 4

Movement of molecules or ions across a membrane from a region of lower concentration to a region of higher concentration, using ATP.

Question 5

Which of the following are passive processes and which are active processes? (2)

• Diffusion
• Osmosis
• Active Transport

Answer 5

Diffusion = Passive.
Osmosis = Passive.
Active Transport = Active.

Question 6

Why is Active Transport an Active process? (1)

Answer 6

Because it requires the energy from ATP.

Question 7

The exchange of urea in the nephron is an example of which type of process? (1)

Answer 7

Diffusion.

Question 8

The exchange of water in root hair cells is an example of which type of process? (1)

Answer 8

Osmosis.

Question 9

The exchange of sucrose in the companion cells of the phloem is an example of which type of process? (1)

Answer 9

Active transport.

Question 10

The exchange of water in the air spaces of leaves is an example of which type of process? (1)

Answer 10

Osmosis.

Question 11

The exchange of mineral ions in the root hair cell is an example of which type of process? (1)

Answer 11

Active transport.

Question 12

The exchange of water in the nephron is an example of which type of process? (1)

Answer 12

Osmosis.

Question 13

The exchange of glucose and a.a’s in the proximal convoluted tubule is an example of which type of process? (1)

Answer 13

Active transport.

Question 14

The exchange of glucose and a.a’s in the ileum is an example of which type of process? (1)

Answer 14

Active transport.

Question 15

The exchange of oxygen and carbon dioxide in the lungs is an example of which type of process? (1)

Answer 15

Diffusion.

Question 16

The exchange of water in the lungs is an example of which type of process? (1)

Answer 16

Osmosis.

Question 17

The exchange of oxygen and carbon dioxide in the respiring cells is an example of which type of process? (1)

Answer 17

Diffusion.

Question 18

The exchange of oxygen and carbon dioxide in the gills is an example of which type of process? (1)

Answer 18

Diffusion.

Question 19

The exchange of oxygen and carbon dioxide in the leaf air spaces is an example of which type of process? (1)

Answer 19

Diffusion.

Question 20

Describe how the SA:V ratio changes as the size of an organism increases. (1)

Answer 20

Decreases, as volume increases more rapidly than surface area.

Question 21

What is the relationship between metabolic rate and SA:V? (1)

Answer 21

Organisms which a higher metabolic rate (rate of respiration) tend to have a larger SA:V.

Question 22

Describe two specialisations which organisms commonly have to increase the rate of diffusion. (2)

Answer 22

• Flattened body

- Specialised gas exchange system

Question 23

Name the 5 features of a specialised exchange surface: (5)

Answer 23

• Large surface area relative to volume.
• Very thin surface.
• Selectively permeable.
• Movement of the environmental medium (air or water).
• Mass transport system.

Question 24

Explain why most specialised exchange surfaces are internal to the body: (2)

Answer 24

• Surfaces are very thin and air is not a dense medium, therefore, not supported and easily damaged.
• Surfaces are a site of extensive water and heat loss, if outside the body, it would lead to dehydration.

Question 25

What is the function of the C shaped rings of cartilage in the trachea and bronchi? (2)

Answer 25

They prevent collapse of airway as pressure falls during inhalation they also allow expansion of oesophagus during swallowing.

Question 26

What is the function of the smooth muscle in the walls of the bronchi and bronchioles? (1)

Answer 26

They allow the diameter of the airways to be altered to control movement of air into the alveoli.