Which of the following is not a function of proteins?

Options

A. Fomation of hair, wool , skin and nails.
B. As a biological catalyst in the form of enzymes.
C. As food in the form of meat, eggs.
D. As energy provider for metabolism

Explanation

To determine which of the following is not a function of proteins, we will analyze each option provided.

1. **Formation of hair, wool, skin, and nails**:
- Proteins such as keratin are essential for the structure of hair, wool, skin, and nails. Keratin is a fibrous protein that provides strength and resilience to these structures. Therefore, this is indeed a function of proteins.

2. **Biological catalysis (enzymes)**:
- Enzymes are specialized proteins that act as catalysts in biological reactions. They speed up chemical reactions without being consumed in the process. This is a well-known function of proteins. Hence, this option is also a function of proteins.

3. **As food (in the form of meat and eggs)**:
- Proteins are a major component of many foods, including meat and eggs. They provide essential amino acids necessary for growth and repair in the body. Therefore, this is also a function of proteins.

4. **As an energy provider to metabolism**:
- While proteins can be used for energy, they are not the primary source of energy for the body. Carbohydrates (like glucose) are the main energy providers. Proteins are primarily used for building and repairing tissues, not primarily for energy. Thus, this option is not a primary function of proteins.

Based on the analysis above, the answer is:

**D. As an energy provider to metabolism** is not a function of proteins.

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