When yeast ferments glucose, the products are:

Options

A. `H_2O+CO_2`
B. methanol and water
C. methanol and `CO_2 `
D. ethanol and `CO_2`

Answer

**Step-by-Step Solution:**

1. **Understanding Fermentation**:
- Fermentation is a metabolic process that converts sugar to acids, gases, or alcohol in the absence of oxygen. It is primarily carried out by certain microorganisms, including yeast.

2. **Identifying the Organism**:
- In this case, the organism responsible for fermentation is yeast, which is a type of fungus.

3. **Recognizing the Substrate**:
- The substrate being fermented is glucose, a simple sugar with the chemical formula C6H12O6.

4. **Chemical Reaction of Fermentation**:
- The process of fermentation by yeast can be represented by the following chemical equation:
\[ C6H12O6 \rightarrow 2 C2H5OH + 2 CO2 + \text{energy} \]
- In this equation, glucose is converted into two molecules of ethanol (C2H5OH) and two molecules of carbon dioxide (CO2), along with the release of energy.

5. **Final Products**:
- Therefore, the products of yeast fermentation of glucose are ethanol and carbon dioxide.

**Final Answer**: When yeast ferments glucose, the products are ethanol and carbon dioxide.

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