SESSION 14

Question 1

Define an antibody

Answer 1

A blood protein produced in response to and. Counteracting a specific antigen
Antibodies combine chemically with substances which the body recognises as alien, such as bacteria, viruses, and foreign substances in the blood

Antibodies bind to specific protein targets (antigens)

Recognises a few amino acid on a protein (epitope)

Question 2

Define antigen

Answer 2

A toxin or other foreign substance which induces an immune response in the body, especially the production or antibodies

Question 3

Define epitope

Answer 3

The part of an antigen molecule to which an antibody attaches itself

Question 4

Define polyclonal antibodies

Answer 4

• produces by many lymphocytes
• multiple different antibodies
• specific to 1 antigen
• multiple epitopes

Question 5

Define monoclonal antibodies

Answer 5

• produces from one B lymphocyte
• one identical antibody
• specific to one antigen
• one epitope

Question 6

Explain how western blotting detects proteins

Answer 6

Western blotting is used widely to detect specific proteins in a tissue extract

Artificial antibodies are created that react with a specific target protein
The sample to be tested is prepared and put together with these antibodies on a membrane - if the specific protein sought for is present, after a gel electrophoresis step this will result in an accordingly stained band on the western blot

Question 7

Describe enzyme- linked immunosorbent assay

Answer 7

The enzyme- linked immunosorbent assay is a test that uses antibodies ad colour change to identify a substance

• antigens from the sample are attached to a surface
• then, a further specific antibody is applied over the surface so it can bind to the antigen
• this antibody is linked to an enzyme, an in the final temp, a substance containing the enzymes substance is added
• the subsequent reaction produces a detectable signal, most commonly a colour change in the substance

Question 8

Explain how enzymes are measured

Answer 8

1) metabolic disorders- in tissue

2) diagnosis of disease - serum enzymes

Question 9

Define how enzyme assays measure the product

Answer 9

Continuous assays:

• spectrophotometry
• chemoluminescene

Discontinuous assays

• radioactivity
• chromatography

Question 10

Explain how serum enzymes are clinically important

Answer 10

• aspartame transaminase (AST)/ alanine transaminase (ALT)- markers for liver damage/ disease
• amylase/ lipase - markers for pancreatitis
• y-glutamic transferase- marker for liver damage increased by alcohol
• alkaline phosphatase- marker for bone disorder

Question 11

Explain measurement of metabolite concentrations using enzymes

Answer 11

Enzymes can be used to measure clinically important metabolites

E.g. Measurement of glucose concentrations with glucose oxidase

    - test strips: H2O2 converted to coloured dye
    - glucose monitor- glucose oxidase used as biosensor

Question 12

What are primers in a PCR reaction and what is their function?

Answer 12

A primer must be synthesised by an enzyme called primase, which is a type of RNA polymerase, before DNA replication can occur

Initiates taq polymerase starts replication at the 3’ end of the primer and copies the opposite strand