General Knowledge » Science »


Made up of Carbon, Hydrogen, Oxygen, Nitrogen and sometimes Sulphur. Important for growth and repair of the body (75% of our body is proteins only).

Made up of amino acids. Amino acids are of 2 Types :

Essential Amino Acids : They cannot be synthesised in the body and must be taken in the diet. They include isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine.

Non – Essential Amino Acids : They are synthesized in the body and do not need to be taken from outside. These include Alanine, Arginine, Asparagine, Aspartic Acid, Cysteine, Glutamine, Glutamic Acid, Glycine, Histidine, Proline, Serine and Tyrosine.

Proteins are first broken into Amino Acids and then Digested.

Some important Proteins are:

  • As Enzymes : As Catalyst in Digestion (Eg. Pepsin, Trypsin).
  • As a Hormone : To regulate body functions (Eg. Insulin, Glucogon, ACTH).
  • In Transport of different Substances : (Eg. Haemoglobin – Transports O2 in blood, Myoglobin – Stores O2 in muscles).
  • As Contractile Proteins for Contraction in Muscles : (Eg. Actin and Myosin).
  • Structural Proteins : (Eg. Collagen – Component – of Connective Tissue, Bones, Tendons, Cartilage Keratin – Component of Skin, Feathers, Nails, Hair, Horn).
  • Protective Proteins : To fight infections (Eg. Gamma globulins).
  • Visual Proteins : Rhodopsin and Iodopsin of rods and cones are proteins only. (Rods and Cones are the cells which are present in Retina of the eye).

General Studies Question Bank CD

About 70 – 100 gms of proteins are daily needed.

Sources : Groundnuts, Soyabean, Pulses, Lean Meat, Fish, Eggs, Milk, etc.

Protein Energy Malnutrition :

In the Age – Group of 1 – 5 Years.

It is primarily due to inadequate intake of Food (particularly proteins) both in quantity and quality. It causes :

Kwashiorkar :

Due to die deficiency of protein.

Means neglected child (when mother stops breast feeding).

Symptoms : Abdomen and feet swells (due to retention of water called oedema), Skin becomes Dark and Scaly, Enlarged Liver, Anaemia.

In infants under 1 Year of age.

Marasmus :

Deficiency of Proteins, Carbohydrates and Fats.

Symptoms : Losing of body weight, wasting of muscles, ribs look prominent. (Oedema and skin pigmentation absent).

In children between 6 months and 3 Years.

General Studies Question Bank CD

JEE Main

Application Form Submission 16 Dec 2020 to 16 Jan 2021.