Question

Lab Questions Biosafety and Aseptic Techniques

1) Why is crucial to learn proper aseptic technique? List at least 3 sources of error if someone used improper aseptic technique when sub-culturing

2. Why is it important to be able to isolate single microbial species for culture?

3. What is the purpose of sub-culturing?

4. Why do you need to cool down a transfer loop after heat sterilization?

Answer 1

Ans 1. Aseptic technique is a most crucial laboratory skill in the field of microbiology. Microbiologists use aseptic technique for a variety of procedures such as transferring cultures, inoculating media, isolation of pure cultures, and for performing microbiological tests. Proper aseptic technique prevents contamination of cultures from foreign bacteria inherent in the environment. Using proper aseptic technique can greatly minimize or even eliminate the risk of contamination. In addition, aseptic technique is of utmost importance to maintain pure stock cultures while transferring cultures to new media. Aseptic technique is also essential for isolation of a single species of microorganism from a mixed culture to obtain a pure culture. Furthermore, proper aseptic technique prevents microbes used in the laboratory from accidentally being released into the environment and/ or infecting people working in the laboratory.Chances of error occur if improper aseptic technique occur during subculturing:

i Contamination in culture

ii Cross contamination with other bacteria

iii Growthn of mycoplasma

Ans 2. The isolation of bacteria in pure culture is important because it facilitates the application of recombinant DNA technology through the isolation of clones.

Ans 3. Subculturing prolongs the lifespan of the cells or microorganisms, allowing for long-term maintenance and observation of the culture. The process of subculturing involves transferring microbes from one growth container to another, providing the microbes with a fresh supply of nutrients on a solid or liquid medium.

Ans 4. It is necessary to cool down the tranfer loop after sterilization because the hot loop may create aerosols when it touches the media containing microorganisms. It will cause some of the broth and bacteria to boil briefly, creating a bacteria-containing aerosol. This airborne bacteria have the chances of entering into the respiratory tract or into the body parts.