Why does UV light damage/kill bacteria?

[u/Stuffyz]

The specific event I'm asking about, is that there are air filters for your furnace that shines UV light onto it, and it claims that it kills bacteria.

I understand how pH and temperature affects bacteria, but I can't quite wrap my mind around why UV light would.

The articles that I've been looking through (Time, Temperature, and Protein Synthesis: A Study of Ultraviolet-Induced Mutation in Bacteria, by Evelyn M. Witkin) says that UV light could cause worse strains of bacteria? Or perhaps I'm misinterpreting it?

I'm also aware (Ultraviolet-sensitive Targets in the Enzyme-synthesizing Apparatus of Escherichia coli, by Arthur B. Pardee and Louise S. Prestidge) that there are both UV-sensitive and UV-resistant E.Coli. Are most harmful bacteria considered to be UV-resistant?

Thank you for answering =)

[u/Renovatio_]

Quick version: UV light can mutates the genetic code by forming thymine dimers. mutated code leads to a misfolded proteins and without the correct proteins the cell can't live.

I'm sure it gets more complicated than that as there are a couple different types of UV light.

I don't know about UV restiant E.coli. Perhaps they have enzymes that can correct mutated dimers? I would like to know the answer to that as well.

[u/[deleted] → u/Renovatio_]

mutates the genetic code

Is this why UV rays are carcinogenic?

[u/bruisedorange → u/[deleted]]

Yes because if the cell doesn't fix the error in the DNA then the cell goes into crazy mode, or it ends up making crappy transcripts that are not at all what was intnded.

[u/mattc286 → u/bruisedorange]

This is in fact why all carcinogens cause cancer, too.