The force of attraction between the neighbouring peptide chains is

Options

A. Vander Waal's force
B. Covalent bond
C. Hydrogen bond
D. Peptide linkage

Explanation

To answer the question regarding the force of attraction between neighboring peptide chains, we need to consider the structure and interactions of peptides.

### Step-by-Step Solution:

1. **Understanding Peptide Chains**: Peptides are short chains of amino acids linked by peptide bonds. Each amino acid has an amino group (-NH2), a carboxyl group (-COOH), and a side chain (R group) that varies between different amino acids.

2. **Peptide Bond Formation**: The peptide bond is formed between the carboxyl group of one amino acid and the amino group of another, releasing a molecule of water (condensation reaction).

3. **Secondary Structure of Proteins**: The arrangement of peptide chains can lead to secondary structures such as alpha-helices and beta-sheets. These structures are stabilized by hydrogen bonds.

4. **Forces of Attraction**: The primary force of attraction between neighboring peptide chains in these secondary structures is hydrogen bonding. Hydrogen bonds occur between the carbonyl oxygen of one peptide bond and the hydrogen of the amine group of another.

5. **Other Interactions**: While hydrogen bonds are the main force, there can also be other interactions such as ionic bonds, hydrophobic interactions, and van der Waals forces, but these are typically secondary to hydrogen bonding in stabilizing the structure of peptides.

### Final Answer:
The force of attraction between neighboring peptide chains is primarily due to **hydrogen bonds**.

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