Anaerobic process

The correct option is A

takes place in yeast during fermentation

The correct option is A.

Explanation of correct option:

1. A kind of cellular respiration in which respiration takes place in the absence of oxygen is anaerobic respiration.
2. Fermentation is an anaerobic pathway, found in both unicellular eukaryotes and prokaryotes.
3. In the process of fermentation, glucose is oxidized partially to produce acids and alcohol.
4. The anaerobic process takes place in yeast at the time of fermentation.
5. The microbes like yeast dissociate the food, that is, glucose into carbon dioxide, and ethanol, and discharge energy in the absence of oxygen.

The reaction is:

${\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6\left(\mathrm{glucose}\right)\to 2{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}\left(\mathrm{ethanol}\right)+2{\mathrm{CO}}_2(\mathrm{carbon}\mathrm{dioxide})+2\mathrm{ATP}$

Explanation of incorrect options:

Option B:

1. The anaerobic process takes place in the absence of oxygen.
2. The process which takes place in the presence of oxygen is aerobic.

Option C:

1. Fermentation takes place in unicellular organisms like yeast and bacteria, apart from this, it also takes place in the muscles of human beings at the time of intense exercise. The phenomenon is termed lactic acid fermentation.
2. During lactic acid fermentation, lactic acid is generated at the time of fermentation from pyruvate by lactate dehydrogenase.

$\mathrm{Glucose}+2\mathrm{ADP}+2{\mathrm{NAD}}^{+}\to \mathrm{Pyruvic}\mathrm{acid}+2\mathrm{ATP}+2\mathrm{NADH}$

$\mathrm{Pyruvic}\mathrm{acid}+2\mathrm{NADH}\to \mathrm{Lactic}\mathrm{acid}+2{\mathrm{NAD}}^{+}$

Option D:

1. During the process of fermentation, glucose is oxidized to produce carbon dioxide, ethanol, and energy.
2. It takes place in the absence of oxygen, and no production of oxygen takes place in the process.

Final answer: Anaerobic respiration takes place in yeast at the time of fermentation.