Question

1. (a)(i) What is respiration? (ii) In a tabular form, state four differences between gaseous exchange and aerobic respiration.
(b)(i) As we breathe in and out, not all the air that gets expelled from the lungs is the residual air. Explain the term residual air. (ii) What is the importance of residual air to mammals?
(c) State four characteristic features associated with respiratory structures.
(d)(i) What is oxygen debt? (ii) Outline three activities that can result in oxygen debt.

Accepted Answer

(a)(i) Respiration is the process by which glucose is broken down to release energy. Respiration is said to be aerobic if it involves oxygen and anaerobic if it does not involve oxygen.
(ii) Differences between gaseous exchange and aerobic respiration:
Gaseous exchange: energy is not released; it occurs outside the body cells; it does not involve enzymatic reactions; it is a physical process.
Aerobic respiration: energy is released; it occurs within the body cells; it involves enzymatic reactions; it is a chemical process.

(b)(i) The air that is left in the lungs (not expelled during normal breathing out) is known as the residual air.
(ii) Residual air is mainly there to prevent the lungs from collapsing.

(c) Characteristics of respiratory structures: they are moist; they are sufficiently vascularised; they have thin membranes; they have a wide surface area.

(d)(i) Oxygen debt refers to the amount of oxygen that is required to get rid of the lactic acid that has accumulated as a result of anaerobic respiration.
(ii) Oxygen debt occurs as a result of strenuous exercises. Activities that can result in oxygen debt include: running, jumping, boxing.

WAEC Biology 2013 Theory — Question 1

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