Gas Exchange

Question 1

The fist molecules xylene bind causes a change I the shape of the haemoglobin molecules

This change of shape makes it easier for other oxygen molecules to bind to he hemoglobin molecules
Explain hiw the graph provides evidence for this
(2)

Answer 1

At a low partial pressure of O2 there is a little increase in the saturation of O2 (1)

The there is a rapid rise as suggesting that it gets easier for O2 to bind to haemoglobin molecules to bind (1)

Question 2

What is partial pressure (1)

Answer 2

It is the measure of the concentration of gas

Question 3

Explain the difference between the figures shown on Table 1 for rest and exercise (4)

Answer 3

Muscle contractions causes increased respiration (1)
Increased CO2 production lowering blood pH (1)
Increased heat released therefore increased (1) temperature (1)
Increased O2 consumption lowering tissue PO2 (partial pressure) (1)

Question 4

Does enriching inspiredair with oxygen have an effect on the amount of oxygen reaching the tissues? Support your answer with evidence form the graph and table 2 ( 3 marks)

Answer 4

Nearly a O2 is transported by hemoglobin (1)

Haemoglobin is nearly nearly full saturated with O2 (95% saturated) (1 mark)

Thefore enriching inapired air with oxygen will raise this to 100% a small 5% increase (1 mark)

Question 5

The xahne yo the dissociation curve is kne of a number of ways in which the total supplied to muscles is increased during wmexercise

Give two other ways in which the total oxygen supplied to muscles during exercise is increased
(2 marks)

Answer 5

Any two of the following:

1. Vasodilation
2. Increased pulmonary ventilation
3. Increases heart rate
4. increasdd stroke rate
5. Increased blood flow rate

Question 6

Explain how the presence of gills adapt the damselfly to its say of life ( 2 marks)

Answer 6

Damselfly larvae has higher metabolic rate so uses ire oxygen