# What is the chemical composition of proteins?

Proteins are organic compounds which are polymers of amino acids.

#### Explanation:

There are 20 different amino acids which make up proteins. Each amino acid consists of a central carbon. The central carbon is bonded to an amine group ($N {H}_{2}$), a carboxyl group (COOH), a hydrogen atom and an R group.

![https://d2jmvrsizmvf4x.cloudfront.net/mzWEWzHlS1Sv4iXF0kzF_amino_acid.jpg)

Amino acids can be linked together when the amine group of one amino acid is bonded to the carboxyl group of a different amino acid. The COOH donates an OH group and the $N {H}_{2}$ donates a H. The OH and H come together to form a water molecule, so this process is called dehydration synthesis - water is removed to form something new. The bond which holds the amino acids together is called a polypeptide.

Here's a video which summarizes key concepts students should know about proteins for a high school biology class.

Video from: Noel Pauller

Hope this helps!