The enzyme concerned with transfer of electrons is -

Options

A. Oxidoreductases
B. Cytochrome oxidase
C. Dehydrogenase
D. All of the above

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the enzyme that is specifically involved in the transfer of electrons. This is a fundamental concept in biochemistry, particularly in cellular respiration.

2. **Identifying the Context**: The electron transfer process is primarily associated with the electron transport chain (ETC), which occurs in the mitochondria of cells. The ETC is crucial for ATP production through oxidative phosphorylation.

3. **Recognizing Key Enzymes**: In the context of the electron transport chain, several enzymes facilitate the transfer of electrons. The main types of enzymes involved include:
- **Oxidoreductases**: These enzymes catalyze oxidation-reduction reactions, transferring electrons from one molecule to another.
- **Cytochrome oxidase**: This is a specific type of oxidoreductase that plays a critical role in the final step of the electron transport chain.
- **Dehydrogenases**: These enzymes also participate in the transfer of electrons and are involved in both the electron transport chain and the citric acid cycle (TCA cycle).

4. **Conclusion**: The enzyme that is primarily concerned with the transfer of electrons in the electron transport chain is **oxidoreductase**. More specifically, **cytochrome oxidase** is a key enzyme in this process.

**Final Answer**: The enzyme concerned with the transfer of electrons is **oxidoreductase** (specifically, cytochrome oxidase).

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