Question

How are peptide bond formed?

Answer 1

Through condensation reactions, where water is released and one amino acid bonds to another.

Explanation:

Amino acids have the basic structure of `NH_2CHCOOHR`, where `R` is a side-chain that varies between one amino acid and another.

They look like this:

![http://www.nutrientsreview.com/proteins/amino-acids]()

When peptide bonds form, between one amino acid and another, the hydroxyl (`-OH`) group of the carboxylic acid and one hydrogen (`-H`) of the amino group fall off, and other amino acids bonds to them.

Carboxylic acid groups bond to amino groups, and vice versa.

The hydroxyl group and hydrogen combine to form water (`H_2O`), which is why this is called a condensation reaction.

An amino acid polymer or polypeptide looks like this:

![https://en.wikipedia.org/wiki/Peptide]()