insects

Question 1

How does insects maintain a concentration gradient?

Answer 1

• Oxygen is continually used by the cells by respiration. Oxygen concentration is lower in the cells than in air, so oxygen will diffuse from air into cells.
• Production of CO2 by respiration in the cells.
• Keeps CO2 conc in cells higher than in air, this leads to diffusion of CO2 out of cell.

Question 2

How do insects have large surface area?

Answer 2

• Tracheoles collectively provides a large surface area.
• Tracheol tubes branch + further divide into tracheoles.
• Withdraw of fluid from the tracheoles during vigorous activity -> further increase surface area.

Question 3

How do insects provide a short diffusion distance?

Answer 3

• Tracheol walls are very thin.
• Very short distance from air in tracheoles to the cells.
• Withdaw of fluid from tracheoles enables air to get closer to the cells.

Question 4

What happens during spiracles?

Answer 4

• Air enters and leaves through the spiracles and water is also lost.
• Spiracle sphincters kept close as much as possible to minimise water loss.
• When an insect is inactive oxygen demands are very low,spiracles will be closed. More active insect is more open sphincters are.

Question 5

What happens in trachea?

Answer 5

• Carries air into body.
• Tubes are lined by chitin, relatively impermeable to gases so little gaseous exchange takes place here.

Question 6

What happens in tracheoles?

Answer 6

This is where most gaseous exchange takes place between air and respiring cells.