Concept explainers
Test Your Understanding
1. Which of the following is a benefit of gas exchange in air compared with gas exchange in water? (a) air has a higher concentration of molecular oxygen (b) oxygen diffuses more slowly in air (c) no energy is required for ventilation (d) moist respiratory surface is not needed (e) air is denser than water
Introduction: The process of gas exchange that occurs between an organism and its environment is known as respiration. For cellular respiration, most of the animal cells need a continuous oxygen supply. During respiration, oxygen is inhaled from the environment and transported to individual cells of the body. Carbon dioxide produced during the cellular respiration is exhaled from the body to the environment.
Answer to Problem 1TYU
Correct answer: A benefit of gas exchange in air compared with gas exchange in water is that air has a higher concentration of molecule oxygen. Hence, the correct answer is option (a).
Explanation of Solution
Reason for the correct answer:
Option (a) is given as “air has a higher concentration of molecular oxygen”.
The benefit of gas exchange in air over gas exchange in water is due to the following reasons:
- Air medium contains high molecular oxygen concentration at least 20 times more than the water medium.
- Energy requirement is less in air medium than the water medium to obtain oxygen.
- Oxygen diffuses faster in air than in water, as air is less dense and less viscous.
Hence, the correct answer is option (a).
Reasons for incorrect answers:
Option (b) is given as “oxygen diffuses more slowly in air”. Diffusion of oxygen is faster in air than in water, as air is less dense and less viscous than water. Hence, option (b) is incorrect.
Option (c) is given as “no energy is required for ventilation”. Energy requirement for ventilation is less in air medium than in in water medium. Hence, option (c) is incorrect.
Option (d) is given as “moist respiratory surface is not needed”. For gas exchange between air and blood, a moist respiratory surface is essential. Hence, option (d) is incorrect.
Option (e) is given as “air is denser than water”. Air is less dense and less viscous than water. Hence, option (e) is incorrect.
Hence, options (b), (c), (d), and (e) are incorrect.
The advantage of gas exchange in air compared with gas exchange in water is that air has a higher concentration of molecule oxygen.
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Chapter 46 Solutions
Biology (MindTap Course List)
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