Microbiology in the lab

Question 1

Define Sterilisation

Answer 1

An absolute term meaning the destruction/removal of all living cells, including spores

Question 2

Define Sterilant

Answer 2

A chemical agent capable of sterilising

Question 3

Define Disinfection

Answer 3

A method which inhibits/eliminates microorganisms which can cause disease

Question 4

Define Disinfectant

Answer 4

Agents used to disinfect inanimate objects

Question 5

Define Sanitisation

Answer 5

A process which reduces the population of microorganisms to a safe level

Question 6

Antiseptic

Answer 6

Applied to living tissues to inhibit growth of pathogens

Question 7

A product which will kill bacteria is

Answer 7

Bactericidal

Question 8

A product that inhibits growth without killing bacteria is

Answer 8

Bacteriostatic

Question 9

What is moist heating?

Answer 9

Degrades nucleic acids, disrupts cell membranes and denatures proteins.

Unable to kill bacterial endospores so further conditions must be used

Question 10

How does autoclave work?

Answer 10

Uses saturated steam under pressure to disinfect

Normal conditions are 121 degrees, 15ib/in2 for 15 mins

Question 11

Why does moist heat benefit us?

Answer 11

Ensures that the microbial cultures provided contain only the pathogen they are labelled as

All equipment is sterilised prior to the organism being introduced

Question 12

What is pasteurisation

Answer 12

A process which controls the heating process to eliminate any significant microbes

Necessary for substances that would be damaged or rendered unusable by boiling

E.g. Milk can be heated at 63 degrees for 30 minutes or 140 degrees for 1-3 seconds

Question 13

What is dry heating?

Answer 13

160 to 170 degrees for 2-3 hours

Primarily used for metals and powders

Main issue is that it is slow

Question 14

Define aseptic

Answer 14

The absence of microorganisms that can cause disease