Page 26 - Q & A STPM 2022 Biology

Biology STPM Chapter 7 Gaseous Exchange

Question 3
Which of these are roles of the carbonic anhydrase enzyme in the process of
gaseous exchange in human beings?
I Increases the release of CO gas into the lung
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II Increases the capillary wall’s ability to absorb oxygen
III Increases the concentration of H ions in the red blood cell
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IV Increases the concentration of HCO ions in the red blood cell
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A I and II C II, III and IV
B I and IV D I, II, III and IV
Answer: D
Carbonic anhydrase is a very efficient enzyme. It is found in the red blood cells
and catalyses the combination of CO and water to form carbonic acid. The
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carbonic acid then dissociates into H ions and HCO ions. Semester
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–
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Question 4 2
The graph below shows three oxygen dissociation curves for three different
animals.

Percentage of saturation of haemoglobin with oxygen P Q R

Partial pressure of oxygen/ pO 2 (kPa)
Which of the following is correct about curves P, Q and R?
A worm in Pigeon Human
waterlogged soil
A P Q R
B P R Q
C Q R P
D R P Q

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Chapter 7.indd 151 11/2/21 9:27 AM