Gas Exchange

Question 1

How do plants exchange waste products of photosynthesis?

Answer 1

Through diffusion in the stomata

Question 2

How are leaves adapted for efficient gaseous exchange?

Answer 2

They are broad so there is a large surface area for diffusion
They are thin for a short diffusion pathway

Question 3

How do the stomata prevent the leaves from drying up?

Answer 3

Stomata close during the dark as photosynthesis cant happen without light so it closes to not let water escape

Question 4

What controls the stomata?

Answer 4

guard cells change their shape and volume to open or close the stomata

Question 5

What to the body when you breathe in?

Answer 5

Intercostal muscles and diaphragm contract
Thorax volume increases
This decreases the pressure, drawing air in

Question 6

What happens to the body when you breathe out?

Answer 6

Intercostal muscles and diaphragm relax
Thorax volume decreases
This increases the pressure forcing air out

Question 7

What are the alveoli?

Answer 7

Site of gaseous exchange

Question 8

How are the alveoli adapted for efficient gaseous exchange?

Answer 8

Large surface area: volume ratio
Moist lining for gases to dissolve in
Thin walls for short diffusion pathway
Good blood supply to maintain a high concentration gradient
Walls are permeable so gases can diffuse across easily

Question 9

How can smoking damage your lungs?

Answer 9

Damages the alveoli which reduces the lungs surface area. This is emphysema
The tar will damage the cilia, this will allow dust and bacteria to reach the lungs making chest infections more likely
Tar also irritates the bronchi and bronchioles, clotting them leading to chronic bronchitis(smokers cough)