Practise IB Biology SL 3.1.3 using exact SL questions on exercise ventilation, alveolar blood flow and maintenance of oxygen gradients.
Compounds of carbon, hydrogen and oxygen are used to supply and store energy.
Describe how a concentration gradient of oxygen is maintained between the lungs and blood capillaries.
a. gas exchange takes place between the alveoli and capillaries;
b. alveoli surrounded by (dense) network of blood capillaries;
c. blood returning to alveolar capillaries is low in oxygen;
d. ventilation brings air rich in oxygen into the alveoli/lungs;
e. there is a higher concentration of oxygen in alveoli than in blood capillaries;
f. oxygen diffuses from alveoli/lungs to capillaries (moves down a concentration gradient);
e. Accept converse.
4 max