Page 40 - Q & A STPM 2022 Biology

Biology STPM Chapter 7 Gaseous Exchange
Answer: D
The breathing is accelerated when the partial pressure of carbon dioxide in the
blood increases.

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Section B Structured Questions

Question 1
Figure 7 below shows the structure involved in human breathing control
mechanism.

Cerebral hemisphere
(voluntary control of
breathing) Semester
Pons
J Cerebellum
2
K

L
M

Figure 7
(a) State the structures labelled J, K, L and M. (2 marks)
J :
K :
L :
M :
(b) Explain the role of J and M in the control of breathing. (1 mark)
J :
M :
(c) State the two main stimuli which affect the rate of breathing. (1 mark)
(d) Explain what happens to the breathing rate as we exercise. (2 marks)
(e) Describe briefly how the breathing rate is brought back to normal.
(2 marks)

165

Chapter 7.indd 165 11/2/21 9:27 AM