Insects Gas Exchange

Question 1

Why do single-celled organisms have a large surface area to volume ratio?

Answer 1

They are small

Question 2

How is oxygen absorbed by single celled organism?

Answer 2

By diffusion across their body surface

Question 3

What feature of an insects body surface allows it to absorb oxygen?

Answer 3

It is covered only by a cell-surface membrane

Question 4

Does carbon dioxide move out of an insect the same way oxygen moves in?

Answer 4

Yes

Question 5

Is a living cell being surrounded by a cell wall an additional barrier to the diffusion of gases?

Answer 5

No

Question 6

Why does the increase in surface area required for gas exchange in an insect conflict with conserving water?

Answer 6

Because the water will evaporate from it

Question 7

What do insects use for gas exchange?

Answer 7

Tracheae- Internal network of tubes

Question 8

What prevents the tracheae from collapsing?

Answer 8

Strengthened rings

Question 9

What dead end tubes are the tracheae divided into?

Answer 9

Tracheoles

Question 10

Why do tracheoles extend throughout all the body tissues of an insect?

Answer 10

Atmospheric air with oxygen is brought directly to the respiring tissues - short diffusion pathway from a tracheole to any body cell

Question 11

What 3 ways do respiratory gases move in and out of the tracheal system?

Answer 11

• Along a diffusion gradient
• Mass transport
• The ends of the tracheoles are filled with water

Question 12

Why does the concentration of oxygen at the end of the tracheoles decrease?

Answer 12

Cells are respiring

Question 13

What does the diffusion gradient created cause?

Answer 13

Gaseous oxygen to diffuse from the atmosphere along the trachea and tracheoles to the cells

Question 14

When is carbon dioxide produced by cells?

Answer 14

During respiration

Question 15

What does the larger concentration of Carbon dioxide create?

Answer 15

A diffusion gradient in the opposite direction

Question 16

What direction does carbon dioxide travel due to the reverse diffusion gradient?

Answer 16

From the ends of the cells to the atmosphere

Question 17

How do muscles in the tracheae create mass transport?

Answer 17

Contraction of muscles squeezes the trachea which enables the mass movement of air in and out

Question 18

What effect does mass transport have on gas exchange?

Answer 18

Speeds up gas exchange

Question 19

How does anaerobic respiration lower the water potential of the muscle cells

Answer 19

Produces lactate which is soluble to lowers the water potential

Question 20

How does water move into the cells from the tracheoles?

Answer 20

Osmosis

Question 21

How does the movement of water draw air in?

Answer 21

The water decreases in volume due to osmosis so draws air in

Question 22

In what state is the final diffusion pathway - and is therefore quicker?

Answer 22

In a gas phase rather than a liquid phase

Question 23

What downside does the ends of the tracheoles being filled with water have?

Answer 23

Has greater water evaporation

Question 24

How are spiracles opened?

Answer 24

Valves

Question 25

Why do insects keep their spiracles closed?

Answer 25

Prevents water loss

Question 26

What is a limitation of the tracheal system?

Answer 26

It relies mostly on diffusion to exchange gases

Question 27

Why are insects of small size?

Answer 27

Creates a short diffusion pathway for efficient diffusion

Question 28

What is the size that the insects can attain limited by?

Answer 28

The length of the diffusion pathway