Question

Which of the following is not a product of respiration?

• A. Carbon dioxide
• B. Water
• C. Oxygen
• D. ATP

Answer 1

The correct option is C

Oxygen

The correct option is C.

Explanation of correct option:

1. The process of producing energy in the form of ATP (adenosine triphosphate) via the oxidation of simple sugar like glucose is respiration.
2. In the cells, the production of glucose takes place by the dissociation of more composite carbohydrates, the process is known as cellular respiration.
3. The process of cellular respiration takes place within the mitochondria.
4. Cellular respiration can take place either anaerobically, that is, in the absence of oxygen, or in the presence of oxygen, that is, aerobically.
5. At the time of aerobic cellular respiration, oxygen is used as a reactant and it reacts with oxygen to produce ATP, which is further used by the cells.
6. The equation for aerobic cellular respiration is:

${\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6+6{\mathrm{O}}_2\to 6{\mathrm{CO}}_2+6{\mathrm{H}}_2\mathrm{O}+\mathrm{ATP}$

Explanation of incorrect options:

Option A:

1. In the process of cellular respiration, carbon dioxide is produced as a by-product.
2. From the mitochondria, carbon dioxide is transported to the red blood cells, then back to the lungs to be exhaled.

Option B:

1. In the process of cellular respiration, water is produced as a by-product.

Option D:

1. In the process of cellular respiration, that is, in the presence of oxygen, ATP is produced as a by-product.
2. This ATP is further used as the energy currency of the cell.

Final answer: Oxygen is not a product of respiration.