Fibrous and globular proteins are formed due to ----- structure of protein

Options

A. Primary
B. Secondary
C. Tertiary
D. Quaternary

Answer

To answer the question "Fibrous and globular proteins are formed due to ----- structure of protein," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Protein Structure**: Proteins have four levels of structure: primary, secondary, tertiary, and quaternary. Each level of structure plays a crucial role in determining the overall shape and function of the protein.

2. **Identifying the Types of Structures**:
- **Primary Structure**: This is the linear sequence of amino acids in a polypeptide chain.
- **Secondary Structure**: This involves the local folding of the polypeptide chain into structures such as alpha-helices and beta-pleated sheets.
- **Tertiary Structure**: This refers to the overall three-dimensional shape of a single polypeptide chain, which is formed by the interactions between the side chains (R groups) of the amino acids. This structure is crucial for the function of the protein.
- **Quaternary Structure**: This involves the assembly of multiple polypeptide chains into a larger functional complex.

3. **Defining Fibrous and Globular Proteins**:
- **Fibrous Proteins**: These proteins have elongated, fibrous shapes and are typically structural in nature (e.g., collagen, keratin).
- **Globular Proteins**: These proteins are more spherical and are often functional proteins (e.g., enzymes, antibodies).

4. **Conclusion**: Both fibrous and globular proteins are primarily determined by their tertiary structure. The tertiary structure dictates how the polypeptide chains fold and interact, leading to the formation of these distinct protein types.

5. **Final Answer**: Therefore, the correct answer to the question is that fibrous and globular proteins are formed due to the **tertiary structure** of proteins.