Question

Fermentation occurs in the
A. Presence of oxygen
B. Absence of oxygen
C. Presence of nitrogen
D. Presence of carbon

Answer 1

Hint:
There are different ways by which glucose is broken down to produce products like ethanol, carbon dioxide, and energy. The energy released is trapped in ATP molecules that are used for doing cellular activities. This breakdown of glucose can either be in the presence of oxygen or in absence of oxygen

Complete answer:
The different ways of glycolysis include aerobic respiration and anaerobic respiration.
The first step in glycolysis in both pathways is the production of pyruvic acid, a three-carbon molecule in the cytoplasm.
In aerobic respiration, pyruvic acid is broken down into carbon dioxide, water, and energy.
It is known as cellular respiration and takes place in the presence of oxygen. For example, human beings use these pathways for the breakdown of glucose.
In anaerobic respiration or fermentation, the glucose is broken down into ethanol, carbon dioxide, and energy in the absence of oxygen. The yeast cells use these pathways of glycolysis. The process of fermentation is widely used in the creation of medicine or fermented food that are rich in antioxidants and healthy to consume.
Thus, the correct answer is Absence of oxygen.

Option ‘B’ is correct

Note:
The energy released during fermentation (2 ATP) is much less than the energy released during cellular respiration (38 ATP). When there is a lack of oxygen present in our cells after an excessive session of exercise, the glucose starts breaking down into lactic acid, a three-carbon molecule that causes muscle cramps.