Question

In the absence of oxygen, what do yeast and some microorganisms use for energy production?

a) Ethyl alcohol
b) Carbon dioxide
c) Lactic acid
d) Alcoholic fermentation

Answer 1

Yeast and some microorganisms use alcoholic fermentation in the absence of oxygen to produce ethanol and carbon dioxide, which aids in energy production and allows the continuation of glycolysis.

Step-by-step explanation:

Alcoholic Fermentation and Energy Production

In the absence of oxygen, yeast and some microorganisms primarily undergo alcoholic fermentation for energy production. The process involves the conversion of sugars, such as glucose, into ethanol (ethyl alcohol) and carbon dioxide (CO2). A balanced chemical reaction representing this fermentation process is: C6H12O6 → 2 C2H5OH + 2 CO2. This is essential for the production of goods like bread, where the carbon dioxide helps the dough rise, and alcoholic beverages, where ethanol is the desired product. Additionally, alcoholic fermentation allows the regeneration of NAD+ necessary for glycolysis, enabling cells to produce ATP even under anaerobic conditions.