Question

Define the following terms:

Answer 1

Pure culture: It is the microbial culture containing single species of organism. Pure culture can be obtained by streaking mixed culture on to plates containing appropriate medium, thereby inoculating single colony in to fresh medium.

Sterile medium: Sterile medium is a medium which is free from microbial organisms or contamination Sterilization is the most important aspect in microbiology and all experiments are founded on it.

Inoculum: Inoculum is starting material obtained from a pure culture to start a new culture. Inoculum can be either colonies obtained from plates or cells present in medium obtained from pure culture.

Aseptic technique: Aseptic technique refers to a procedure which is performed in sterile conditions. There are stringent rules and procedures need to be implemented in order to carry out aseptic technique to reduce the risk of contamination and risk of infections.

Example: Using flame sterilization while handling cultures and wearing gloves during the inoculations etc.,

Subculture: Subculture is a method of transferring old microbiological culture in to new medium. This is done to prolong the life of pure culture or obtaining high amount of pure culture.

Colony: Microbial colony is a group of visible cells growing on a solid surface. Colony is defined to be originated from a single ancestor and are genetically identical assuming that there is no contamination.

Contamination: Contamination is defined as the presence of undesired entity (usually microbes such as bacteria, fungi, mould, yeast, prions or toxins) or impurities in the culture or medium. Contamination can be reduced by following aseptic techniques and sterilization methods.

Culture media: Culture media is a food source for microbes which contains all essential elements for growth. Culture media can be in either solid form (With agar) or liquid form (Broth).