gas exchange in single celled organisms and insects

Question 1

Describe how single celled
organisms exchange gases

Answer 1

Single celled organisms are small and therefore have a large
surface area to volume ratio. This is sufficient to exchange the
substances required

Question 2

explain how diffusion gradients allow the exchange of gases by insects

Answer 2

cells respire taking in oxygen from the trachioles as trachioles have a low concentration of oxygen
atmosphere has a higher concentration of oxygen so by diffusion oxygen moves into trachioles

Question 3

explain how mass transport aids the exchange of gases by insects

Answer 3

muscle contraction squeezes the trachea which moves air

Question 4

explain how water in tracheoles allows the exchange of gases by insects

Answer 4

insects carry out intensive exercise during which enough oxygen isn’t available so they carry out anaerobic respiration which produces lactic acid this decreases the water potential of cells

water moves from tracheoles in cell by osmosis. Therefore lowering the volume in tracheoles so air is drawn in so the rate of diffusion increases as oxygen is in a gas phase not a liquid phase

Question 5

what are tracheoles and what function do they provide

Answer 5

small dead end tubes leading from trachae. Extend through the body of the insect direct to respiring tissues providing a short diffusion pathway from air to cells

Question 6

what are trachea and what function do they provide

Answer 6

internal network of tubes supported by strengthened rings to prevent collapse

Question 7

what are spiracles

Answer 7

pores on surface of insect leading to trachea, can be opened and closed