Gas exchange in insects

Question 1

How is gas-exchanged in single-celled organisms?

Answer 1

• Oxygen is absorbed by diffusion across their body surface

Question 2

Do single celled organisms have cell walls?

Answer 2

Single celled organisms only have cell surface membranes, which is completely permeable and so there is no barrier to the diffusion of gases

Question 3

What two processes do insects have to balance?

Answer 3

Gas exchange and water conservation

Question 4

How do insects reduce water loss?

Answer 4

• Waterproof coverings over their body surfaces

- Small surface area to volume ratio

Question 5

How do insects exchange gases?

Answer 5

• Oxygen is brought directly to the respiring tissue via tracheae and tracheoles

Question 6

How do gases move in and out of the tracheal system?

Answer 6

• Along a diffusion gradient

- Ventilation

Question 7

What does the diffusion gradient do?

Answer 7

• As oxygen is used up by respiring cells, its concentration decreases, causing oxygen to move down the tracheole down the diffusion gradient to replace it. Similarly, carbon dioxide is produced by respiration, and so diffuses out along a diffusion gradient in the opposite direction

Question 8

What is ventilation?

Answer 8

Ventilation is the movement of muscles in insects which create mass omvements of air in and out of the tracheae, speeding up gas exchange

Question 9

What are spiracles?

Answer 9

Spiracles are ting pore on the body surface, which can be opened and closed by a valve

Question 10

Can water evaporate from spiracles when they are open?

Answer 10

Water can evaporate from the spiracles when they are open

Question 11

How do insects control water loss?

Answer 11

Insects control water loss by closing their spiracles, and periodically opening them for gas exchange

Question 12

Why is the tracheal system an efficient method of gas exchange?

Answer 12

• Oxygen delivered directly to respiring tissue