All enzymes are

Options

A. proteins
B. lipids
C. fats
D. inorganic catalysts

Answer

**Step-by-Step Solution:**

1. **Understanding Enzymes**: Enzymes are biological catalysts that speed up chemical reactions in living organisms. They play a crucial role in various biochemical processes.

2. **Composition of Enzymes**: The majority of enzymes are composed of proteins. Proteins are made up of long chains of amino acids that fold into specific three-dimensional shapes, which are essential for their function.

3. **Structure of Enzymes**: Like all proteins, enzymes have a specific structure that includes:
- **Primary Structure**: The sequence of amino acids in the polypeptide chain.
- **Secondary Structure**: The local folding of the polypeptide chain into structures such as alpha-helices and beta-sheets.
- **Tertiary Structure**: The overall three-dimensional shape of a single polypeptide chain.

4. **Exceptions to the Rule**: While most enzymes are proteins, there are exceptions. Some enzymes are made up of nucleic acids. A notable example of this is ribozymes, which are RNA molecules that can catalyze chemical reactions.

5. **Conclusion**: Therefore, the statement "All enzymes are proteins" is mostly true, but it is important to remember that there are exceptions like ribozymes.

**Final Answer**: All enzymes are primarily proteins, but some, like ribozymes, are made of nucleic acids.

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