Chapter 23.1, Problem 5SSC

Interpretation Introduction

Interpretation:

The roles of proteins in cells should be explained with example of each role.

Concept introduction:

Proteins are polymeric biomolecules which are formed by the polymerisation of amino acids. Amino acids are the organic molecules with $–{\text{NH}}_{\text{2}}$ and −COOH functional groups bonded on same carbon atom of the molecule.

They polymerise by peptide linkage to form dipeptide, oligopeptide and polypeptide molecules. Each peptide bond formation is a condensation reaction that occurs with the elimination of water molecule.

Explanation of Solution

The polymeric biomolecules which are formed by the polymerization of amino acids are known as proteins.

The four major roles of proteins in cell are:

1. Proteins provide structural support to the body. The most abundant class of proteins present in nature are known as structural proteins. These are fibrous proteins such as collagen that is utilized in the applications of cell structure. Structural proteins provide structural support to organisms for their survival such as Collagen. These are found in connective tissues such as ligament and tendons.
2. Proteins help in the removal of foreign substances from the body and protect the body from infection. The example of this type of proteins is antibodies which are produced by plasma cells.
3. Proteins show the function of enzymes as well. The example of this type of protein is papain. This acts as a catalyst which breaks the proteins and form free amino acids.
4. Proteins also act as a transport. The example of this type of protein is haemoglobin. This carries or transport oxygen in the blood from the lungs to other parts of the body.