What is dissolved in blood plasma?
A. carbon dioxide, erythrocytes and platelets
B. amino acids, glucose and urea
C. carbon dioxide, oxygen and heat
D. glycogen, antibodies and urea
Answer/Explanation
Markscheme
B
What is the state of the atrio-ventricular and semilunar valves when the left ventricle contracts?
Answer/Explanation
Markscheme
D
The diagram below shows the human heart. What structures are indicated by the labels X, Y and Z?
Answer/Explanation
Markscheme
D
Dialysis membrane was set up to model digestion and absorption in the small intestine.
What is a limitation of this model?
A. There can be no active transport.
B. Maltose will pass through the membrane.
C. Lipase should be present with protein.
D. The membrane is not permeable to starch.
▶️Answer/Explanation
Markscheme
A
A dialysis membrane can be used to model digestion and absorption in the small intestine. It is an accurate model because both are partially permeable so smaller particles can pass through the membrane whilst larger particles cannot; the membrane therefore allows the passive movement of solutes in diffusion, and water molecules in osmosis.