Question

Sometimes when we do heavy exercise, anaerobic respiration takes place in our muscle cells. What is produced during this process?

• A. alcohol and lactic acid
• B. alcohol and CO₂
• C. lactic acid and CO₂
• D. lactic acid only

Answer 1

The correct option is D

lactic acid only

The correct option is D.

Explanation of the correct option:

1. Due to the need for a lot of energy to conduct strenuous exercises like running, cycling, weightlifting, and so on, which results in a temporary oxygen deficit in the muscle cells.
2. In the absence of oxygen, the cell of the organism undergoes anaerobic respiration, which converts glucose in muscle cells to lactic acid.
3. This also releases energy, albeit to a lesser extent.
4. $\mathrm{Glucose}\to \mathrm{Lactic}\mathrm{acid}+\mathrm{Energy}$

Explanation of the incorrect options:

Option A:

1. Lactic acid overproduction causes muscle weariness and cramping.
2. Exercising after drinking, the liver will have to work harder to get rid of the toxins from the alcohol.
3. It means it will take longer to clear up the lactic acid, increasing your chances of cramps.

Option B:

1. When a person exercises, the body requires more energy, which means body tissues use more oxygen than at rest.
2. Because the metabolic rate of a person increases as that person uses more oxygen, and hence will also produce more carbon dioxide.

Option C:

1. Because glucose isn't entirely broken down, the amount of energy released is lower than during aerobic respiration.
2. During severe activities, the muscles accumulate lactic acid.
3. Later on, the lactic acid must be oxidized to produce carbon dioxide and water.

Final answer: Sometimes when we do heavy exercise, anaerobic respiration takes place in our muscle cells. Lactic acid is produced during this process.