lab techniques

Question 1

five examples of hazards in the lab:

Answer 1

*toxic chemicals
*corrosive chemicals
*heat and flammable substances
*pathogenic organisms
*mechanical equipment

Question 2

what is a risk?

Answer 2

the likelihood of harm arsing from a hazard

Question 3

what is a risk assessment?

Answer 3

identifying risk levels and control measures which can be used to minimise the risk

Question 4

describe linear dilution:

Answer 4

start with a stock solution (eg. 1M) , add increasing volumes to of that solution to separate tubes and add pure solvent (water) to each tube so that an equal volume of each dilution is produced

Question 5

describe log dilution:

Answer 5

differ by constant proportion (10-1, 10-2 etc) often used in microbiology to estimate concentration or density of cells

Question 6

what is centrifugation used for?

Answer 6

to separate substances by density

Question 7

what is paper and thin layer chromatography used for?

Answer 7

separation of amino acids and sugars

Question 8

what is affinity chromatography used to separate?

Answer 8

target proteins

Question 9

what is the difference between native PAGE and SDS-PAGE gel electrophoresis?

Answer 9

native PAGE does not denature the molecules but SDS-PAGE does

Question 10

what is Native PAGE gel electrophoresis?

Answer 10

separates molecules by size, shape and charge - does not denature molecules but is difficult to carry out

Question 11

what is SDS-PAGE gel electrophoresis?

Answer 11

denatures molecules by giving them an equally negative charge - separates by size alone and simple to carry out

Question 12

what is Isoelectric point?

Answer 12

the pH value at which proteins have an electrically neutral charge, at this point proteins lose solubility and begin to precipitate put of solution

Question 13

summarise immunoassay techniques:

Answer 13

antigens are present in assay material, a labelled antibody is added containing a reporter enzyme. the container is washed out removing unattached antibodies. A colourless substrate of the reporter enzyme is added will produce a coloured product indicating that antibodies are present

Question 14

what is western blotting?

Answer 14

a technique following SDS-PAGE gel electrophoresis. The separated proteins are transferred onto a solid medium and and dried.

Question 15

what is a monoclonal antibody?

Answer 15

stocks of specific antibodies that are specific to a particular antigen