answer of bio book e
Suggested answers to Exercise and Reading to learn
(Note: The overseas examination boards bear no responsibility for the suggested answers contained in this publication. Answers for HKCEE and HKALE questions are not available due to copyright restrictions.
Chapter 3 Regulation of gas content in blood
Exercise
Multiple-choice questions (p. 77)
1 A
2 D
3 C
Short questions (p. 77)
4 a SA node 1m b i To allow the complete emptying of the atria before the ventricles contract. 1m OR To allow ventricles to be filled before contraction. 1m ii To force the blood upwards into the arteries / blood vessels / out of the heart. 1m
5 HKALE Biology 2003 II Q4c
6 a Medulla oblongata 1m b i Heart rate increases. 1m ii Heart rate increases. 1m c The impulse spreads through the atria / right atrium / cardiac muscle 1m to the atrioventricular node, 1m then to the base of the ventricles along the septum. 1m
Structured questions (p. 78)
7 a i Fall in pH / increase in acidity / carbon dioxide level 1m ii Respiration occurring inside the cells 1m b The respiratory centre sends impulses 1m to the diaphragm muscles / intercostal muscles, causing them to contract. 1m c As lungs inflate, the frequency of impulses from stretch receptors 1m to medulla oblongata / respiratory centre increased. 1m
These impulses inhibit the respiratory centre / cause the relaxation of intercostal / diaphragm muscles. 1m
8 HKCEE Biology 2003 I Q1a
9 a Increasing carbon dioxide concentration leads to a slow and then rapid increase in the rate of breathing. 1m The rate becomes more pronounced above a concentration of 5.5% / at 6.0%. 1m b (2100 × 27 – 670 × 14) / (670 × 14) × 100% 1m = 504% 1m c Any four from: 1m x 4
Rise in carbon dioxide concentration is detected by chemoreceptors in aortic / carotid bodies / medulla oblongata. Nerve impulses are sent to medulla oblongata / respiratory centre. Impulses are sent to diaphragm and
(Note: The overseas examination boards bear no responsibility for the suggested answers contained in this publication. Answers for HKCEE and HKALE questions are not available due to copyright restrictions.
Chapter 3 Regulation of gas content in blood
Exercise
Multiple-choice questions (p. 77)
1 A
2 D
3 C
Short questions (p. 77)
4 a SA node 1m b i To allow the complete emptying of the atria before the ventricles contract. 1m OR To allow ventricles to be filled before contraction. 1m ii To force the blood upwards into the arteries / blood vessels / out of the heart. 1m
5 HKALE Biology 2003 II Q4c
6 a Medulla oblongata 1m b i Heart rate increases. 1m ii Heart rate increases. 1m c The impulse spreads through the atria / right atrium / cardiac muscle 1m to the atrioventricular node, 1m then to the base of the ventricles along the septum. 1m
Structured questions (p. 78)
7 a i Fall in pH / increase in acidity / carbon dioxide level 1m ii Respiration occurring inside the cells 1m b The respiratory centre sends impulses 1m to the diaphragm muscles / intercostal muscles, causing them to contract. 1m c As lungs inflate, the frequency of impulses from stretch receptors 1m to medulla oblongata / respiratory centre increased. 1m
These impulses inhibit the respiratory centre / cause the relaxation of intercostal / diaphragm muscles. 1m
8 HKCEE Biology 2003 I Q1a
9 a Increasing carbon dioxide concentration leads to a slow and then rapid increase in the rate of breathing. 1m The rate becomes more pronounced above a concentration of 5.5% / at 6.0%. 1m b (2100 × 27 – 670 × 14) / (670 × 14) × 100% 1m = 504% 1m c Any four from: 1m x 4
Rise in carbon dioxide concentration is detected by chemoreceptors in aortic / carotid bodies / medulla oblongata. Nerve impulses are sent to medulla oblongata / respiratory centre. Impulses are sent to diaphragm and