Question

3. From your text, lecture, or your own experience list two medical examples of how ultraviolet light is used to control microorganisms.

Answer 1

1. In medical UV light sterilization is often used to sterilize the bacterial contamination from the surfaces of the different instruments like scissors, bandages, stethoscopes etc. that are required in daily practice of medical professionals and surgical theaters.

These are kept in UV light for 15-20 minutes for microbial decontamination.

2. For cell culture also in medical laboratory, the laminar hood used for the culture practices are UV sterilized for 15-20 minutes with all the pipettes, tip boxes, inoculating loops, microplates, petri dishes etc. under direct UV light.

UV light does not penetrate surfaces and packaging as it is a non-ionizing radiation. It causes the formation of thymine dimers in the DNA single strand that leads to formation of mutations in the bacterial cells because of the inability of DNA polymerase to incorporate complementary nucleotides and thus kills it.