things i forget a lot

Question 1

describe what you must do when using a colorimeter

Answer 1

• calibrate with an appropriate blank as a baseline
• use absorbance to determine concentration of a coloured solution using suitable wavelength filters
• use of percentage transmission to determine turbidity

Question 2

how does SDS PAGE work

Answer 2

• separates proteins by size alone
• gives all the molecules an equally negative charge and denatures them

Question 3

how do immunoassay techniques work

Answer 3

• they detect and identify specific proteins
• they use stocks of antibodies with the same specificity
• an antibody specific to the protein antigen is linked to a chemical label
• the label is often a reporter enzyme producing a colour change
• other reporters can be used such as chemiluminescence and fluorescence
• in some cases the assay will use a specific antigen to detect the presence of antibodies

Question 4

how does western blotting work

Answer 4

• this is used following SDS PAGE
• the separates proteins from the gel are transferred (blotted) onto a solid medium
• the proteins can be identified using specific antibodies that have reporter enzymes attached

Question 5

what is bright field microscopy often used for

Answer 5

observing whole organisms, parts of organisms, thin sections of dissected tissue or individual cells

Question 6

how does fluorescence microscopy work

Answer 6

uses fluorescent labels to bind to and visualise certain molecules or structures within cells or tissues

Question 7

what does aseptic technique involve

Answer 7

sterilisation of equipment and culture media by heat or chemical means and subsequent exclusion of microbial contaminants