Cambridge International A Level Biology Revision Guide

Chapter 14: Homeostasis
End-of-chapter questions
1 Which of the following is an incorrect statement about the homeostatic control of the concentration of
glucose in the blood?
A Negative feedback is involved in the control of blood glucose.
B The concentration of glucose in the blood fluctuates within narrow limits.
C The hypothalamus is the control centre for blood glucose.
D The liver is an effector organ in blood glucose homeostasis. [1]
2 Glucose is small enough to be filtered from the blood in glomeruli in the kidney, but is not normally found in
the urine. This is because glucose is:
A reabsorbed in distal convoluted tubules
B reabsorbed in proximal convoluted tubules
C reabsorbed along the whole length of the nephrons
D respired by cells in the kidney [1]
3 Which of the following occurs in the body in response to the secretion of glucagon?
A conversion of glucose to glycogen in liver cells
B decrease in the blood glucose concentration
C increased uptake of glucose by muscle cells
D production of cyclic AMP in target cells [1]
4 In response to dehydration, ADH is secreted by the posterior pituitary gland. One of its effects is
to stimulate:
A a reduction in the glomerular filtration rate
B an increase in the number of aquaporins in the cell membranes of collecting duct cells
C an increase in the uptake of water by cells in the proximal convoluted tubules of nephrons
D an increase in the volume of urine produced by the kidneys [1]
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5 Rearrange the following statements to make a flow diagram of the mechanism of opening a stoma.
1 volume of guard cell increases
2 H + transported out of guard cells
3 water enters guard cells by osmosis
4 K + diffuses into guard cells
5 guard cells curve to open stoma
6 water potential of guard cells falls
7 K + channels open [4]