Formation of Amino Acids MCQ - Practice Questions with Answers

Amino Acids

• Amino acids are the monomers that form the polymer called polypeptide or protein. 
• Proteins in humans and other organisms are built from a collection of 20 alpha-amino acids.
• An alpha-amino acid contains a chiral carbon that is bound to an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom and an R-group (side chain).
  

Properties of amino acids:

1. Zwitterions: 

• At the neutral pH, amino acids exist in their zwitterion form. 
• This means that amino acids contain a positive charge and a negative charge. 
• At the low pH of 1.0, the carboxylic acid group is protonated. So, the amino acid exists as a positively charged species.
• At a high pH, the amino group loses its H+ and the amino acid exist as negatively charged species.

2. R- Group- Amino acids can be classified according to their R-group or side chains:
The following figures describe the different types of amino acids: