GIANT MOLECULES – PROTEINS

CONTENT

1. What are Proteins?
2. Sources of Proteins
3. Structure and Shape of Proteins
4. Formation of Peptides
5. Properties of Proteins
6. Test for Proteins
7. Uses of Proteins
8. Enzymes

What are Proteins?

Proteins are one of the four major groups of macromolecules or polymers that are present in all living organisms carrying out various functions needed by cells. They may be regarded as the products needed by cells. They may be regarded as the products of successive condensations between the carboxyl group of one amino acid and the amino – group of another amino-acid. The structure of most enzymes indicates that they are proteins.

Sources of Proteins

Proteins are found in all living systems as structural components and as biologically important substances such as hormones enzymes and pigments.  Proteins in our food contain essentially amino acids and these are called first class proteins. They are mainly of animal origin. Examples include lean meat, fish, eggs, milk, cheese and chicken second class proteins are of plant origin and are found in vegetables, legumes (e.g.