Question

What is the key difference among the 20 amino acids that are used to make proteins?

Answer 1

Answer:

Attached R side groups

Explanation:

The proteins are one of the important biomolecules which are directly coded by the genetic material of an organism.

The proteins are composed of the amino acids which possess, an amine group, a carboxylic group and an attached side group called the R group.

It is the R group of an amino acid which determines whether the amino acid will a polar or a non-polar amino acid molecule thus it determines the properties of the amino acid in terms of chemical properties. The R side group are involved in the formation of bonds with the substrate of the environment and the tertiary structure of the proteins.

Thus, the presence of different R group is the key difference in 20 amino acids.

Answer 2

Answer:

The side groups present in amno acids makes the 20 amino acids different from each other.

Explanation:

Amino acids are used by each cell of living body in order to build the proteins  required to survive. Amino acids consist of two-carbon bond, one is carboxyl group (COO-) and teh other carbon connected to the amino group.

There are total 50 amino acids out of which only 20 are used to make proteins in our body. The side groups present in these 20 amino acids amke them different from each other and used to make protein. Amino acid made up of carboxyl group -COOH , an amine group -NH2 , and atom of H, and variable radical -R.

The side groups are named as polar or non-polar groups or sometimes also called "R" groups. The side goups are responsible to interact with the environment. The polar and nonpolar chemical properties of amino acid allow them to become  hydrophilic (Polar) and hydrophobic (non-polar).

Example: Serine - C3H7NO3 (side chain of HOH2C- )

               Asparagine - C4H8N2O3 (side chain of H2N - CO- CH2-)

Hence, the "R" group is responsible for the variation in 20 amino acids.