B8 Exchange and Transport in Animals

Question 1

What are the three factors affecting the rate of diffusion?

Answer 1

1. Concentration gradient
2. Diffusion distance
3. Surface area

Question 2

How are the alveoli adapted for gas exchange?

Answer 2

1. Large surface area
2. Many millions of alveoli in the lungs
3. Thin cell wall - one cell thick

Question 3

What are the adaptations of red blood cells (erethrocytes)?

Answer 3

1. Biconcave disc shape for large surface area: volume ratio
2. No nucleus for more room to carry oxygen
3. Haemoglobin which binds to oxygen to form oxyhaemoglobin

Question 4

What is the function of phagocytes?

Answer 4

They surround and engulf foreign cells with enzymes

Question 5

What is the function of lymphocytes?

Answer 5

They produce antibodies which bind to foreign cells and destroy the cells

Question 6

What is the function of platelets?

Answer 6

They are fragments of cells that help the blood to clot into a wound

Question 7

What is the function of plasma?

Answer 7

The liquid part that carried the cells round in circulation - straw-coloured

Question 8

What is the function of arteries?

Answer 8

They carry blood away from the heart

Question 9

What is the function of capillaries?

Answer 9

They are involved in the exchange of materials at the tissues

Question 10

What is the function of the veins?

Answer 10

They carry the blood to the heart

Question 11

What are the properties of arteries?

Answer 11

1. High pressure
2. Thick walls to withstand pressure
3. Smaller lumen size to maintain pressure
4. Elastic fibres stretch from increased blood pressure and then recoil when the heart relaxes, giving smooth blood flow

Question 12

What are the properties of capillaries?

Answer 12

1. Thin cell wall - one cell thick
2. Permeable wall
3. Arteries branch into capillaries

Question 13

What are the properties of veins?

Answer 13

1. Capillaries join up to form veins
2. Thinner walls due to lower pressure
3. Bigger lumen to help blood flow
4. Valves to keep blood flowing in the right direction

Question 14

What is respiration?

Answer 14

The process of releasing energy from the breakdown of organic compounds

Question 15

What is the word equation for aerobic respiration?

Answer 15

glucose + oxygen —-> carbon dioxide + water

Question 16

What is the word equation for anaerobic respiration?

Answer 16

glucose —> lactic acid

Question 17

What is the word equation for anaerobic respiration in plants?

Answer 17

glucose —> ethanol + carbon dioxide