Chemicals (part of quiz 8)

Question 1

In general, what do toxic chemicals do to microbes?

Answer 1

generally they kill microbes by disrupting proteins, membranes, and DNA

Question 2

Seven types of chemicals

Answer 2

Cationic detergens, alcohols, heavy metals, aldehydes, peroxygens, halogens, and phenolic compounds

Question 3

Cationic detergents
- know what the chemical is, know its beneficial properties, and how it kills/destroys microbes

Answer 3

soap
- interacts with phospholipids and dissolves membranes
- cheap, relatively nontoxic
- most used disinfectant in the world

Question 4

Alcohols
- know what the chemical is, know its beneficial properties, and how it kills/destroys microbes

Answer 4

60-85% alcohols
- denature proteins and dissolve membranes
- great for skin and surfaces
- evaporates quickly and leaves no residue

Question 5

Heavy metals
- know what the chemical is, know its beneficial properties, and how it kills/destroys microbes

Answer 5

generally, any heavy metal that is microbial (incl. Ag and Cu)
- denature proteins by reacting w/ sulfhydryl groups
- silver nitrate useful on burns and infant eyes

Question 6

Aldehydes
- know what the chemical is, know its beneficial properties, and how it kills/destroys microbes

Answer 6

aldehydes, incl. formaldehyde
- alkylates proteins/DNA and kills all types of microbes (sterilant)
- used to disinfect surfaces and medical equipment
- preservative in vaccines

Question 7

Peroxygens
- know what the chemical is, know its beneficial properties, and how it kills/destroys microbes

Answer 7

peroxygens incl. H2O2
- oxidize lipids, proteins, and DNA
- biodegradable, safe for most materials
- useful on wounds and to disinfect objects

Question 8

Halogens
- know what the chemical is, know its beneficial properties, and how it kills/destroys microbes

Answer 8

halogens incl. Cl, I, F, and bleach
- oxidize lipids, proteins, and DNA
- used to disinfect water, skin, and instruments

Question 9

Phenolic compounds
- know what the chemical is, know its beneficial properties, and how it kills/destroys microbes

Answer 9

compound consisting of a hydroxyl group bonded to a hydrocarbon group
– incl chlorhexidine and triclosan
- denatures proteins
- used in mouthwashes, soaps, lotions, and toothpastes