Chemically, enzymes are

Options

A. (a) fats
B. (b) Carbohydrates
C. (c) hydrocarbons
D. (d) Proteins

Answer

**Step-by-Step Solution:**

1. **Understanding Enzymes**: Enzymes are biological catalysts that speed up chemical reactions in living organisms. They are crucial for various metabolic processes.

2. **Chemical Composition**: Enzymes are primarily composed of proteins. This means that their structure and function are derived from amino acids, which are the building blocks of proteins.

3. **Structure of Enzymes**: Enzymes have a specific three-dimensional structure that includes an active site. The active site is the region where substrates bind, and it is highly specific to the substrate it acts upon.

4. **Specificity of Enzymes**: The specificity of enzymes can be explained by the "lock and key" model, where the enzyme (lock) is specific to its substrate (key). Only the correct substrate can fit into the active site of the enzyme.

5. **Conclusion**: Since enzymes are made up of proteins, the correct answer to the question "Chemically, enzymes are" is that they are proteins.

**Final Answer**: Enzymes are chemically proteins.

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