Question

An agent that prevents the growth of bacteria (without killing) is known as
A.Antibodies
B.Bacteriostatic
C.Bactericide
D.None of the above

Answer 1

Hint:Bacteriostatics does not let bacteria to proliferate. It only prevents growth and does not kill them whereas Bactericide kills bacteria. Antibodies are glycoproteins and are Y-shaped, made up of four peptide chains.

Complete answer:Bacteriostatic are chemical agents that prevent bacteria from reproducing, while not killing them. Therapies in which bacteriostatic antimicrobials are used should provide enough time to the host, to activate its defense mechanism to completely remove the bacteria. After the removal of the bacteriostat, the bacteria regain their capability to grow and start proliferating.
Bactericide kills bacteria. They are usually disinfectants, antiseptics, or antibiotics.
Antibodies are glycoproteins and are Y-shaped. Each antibody is made up of four peptide chains, two heavy and two light connected with the help of disulfide bonds.
Antibody molecules may remain bound to the cell membrane of B cell or may remain free. The free antibody has three main functions:
1. Agglutination reaction(of bacteria and viruses as well)
2. Opsonization or coating of bacteria to facilitate phagocytosis by cells
3. Neutralization of toxins released by bacteria e.g., tetanus toxins.
So, the correct answer is option B. Bacteriostatic.

Note:Each chain of the antibody has a variable region to attach to the epitope of pathogen and a constant region to which carbohydrate residue is attached. Two identical fragments of Y-shaped molecules have antigen-binding sites called fragment antigen-binding (Fab). The fragment which cannot bind an antigen and can be crystallized, known as fragment crystallizable (Fc).