2g

Question 1

Thorax

Answer 1

The ribs, intercostal muscles, diaphragm, trachea, bronchi, bronchioles, alveoli and pleural membranes.

Question 2

Role of intercostal muscles and diaphragm

Answer 2

Breathing in: Increase volume
External intercostal muslces contract to move ribs up and out
Diaphragm contracts and moves down

Breathing out: Decrease volume
External intercostal muscles relax to move ribs down and in
Diaphragm relaxes and moves up

Question 3

Plant gas exchange (Hydrogen Carbonate)

Answer 3

If light is present, the plant will photosynthesise; it will absorb carbon dioxide and release oxygen. Hydrogen carbonate indicator will stay red.
If no light is present, the plant will respire; it will absorb oxygen and release carbon dioxide. Hydrogen carbonate indicator will turn orange/yellow.

Question 4

Effects of smoking

Answer 4

• Addictive: Has nicotine
• Increased risk of cancer: Has tar
• Reduced abilty to carry oxygen: Has carbon monoxide
• Increaded risk of bronchits and emphysema

Question 5

Alveoli adaptation

Answer 5

• Thin - 1 cell thick
• Permeable - Gasses can pass easily
• Large surface area
• Many alveoli
• Concentration gradient - Breathing and blood flow maintain this
• Good blood supply - Capillary network
• Short diffusion pathway

Question 6

Effect of exercise on the release of carbon dioxide

Answer 6

By increasing exercise intesity or amount, breathing rate increases. Thus the amount of carbon dioxide released is higher.

Question 7

How do gases enter and exit the leaf

Answer 7

By diffusion

Question 8

Role of pleural membrane

Answer 8

Attaches the lung to the muscles. Surrounds the whole lung.