When a yeast produces wine, which is not formed ?

Options

A. Acetaldehyde
B. Ethyl Alcohol
C. `CO_2`
D. Acetyl coenzymeA

Answer

### Step-by-Step Solution:

1. **Understanding the Process**: Yeast produces wine through a process called fermentation, which occurs under anaerobic conditions (absence of oxygen).

2. **Glycolysis**: The first step in the fermentation process is glycolysis, where one molecule of glucose is converted into two molecules of pyruvate. During this process, two ATP molecules are generated.

3. **Formation of Intermediate Compounds**: Under anaerobic conditions, the pyruvate is further processed. It is converted into acetaldehyde, and during this conversion, two molecules of carbon dioxide are released.

4. **Final Product Formation**: The acetaldehyde is then converted into ethanol (ethyl alcohol), which is the final product of the fermentation process.

5. **Identifying the Compounds**: In the options provided:
- Acetaldehyde is formed as an intermediate compound.
- Ethyl alcohol (ethanol) is the final product.
- Carbon dioxide is also released during the process.
- Acetyl CoA is not mentioned or formed at any stage in the fermentation process.

6. **Conclusion**: Therefore, the compound that is not formed when yeast produces wine is **Acetyl CoA**.

### Final Answer:
**D. Acetyl CoA is not formed when yeast produces wine.**

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