1.1 Laboratory Techniques

Question 1

Hazard

Answer 1

A source of potential harm

Question 2

Risk

Answer 2

The likelihood of harm arising from exposure to a hazard

Question 3

Risk Assessment

Answer 3

Involves identifying risks and control measures to minimise them

Question 4

Linear Dilutions

Answer 4

Often used when substance being diluted is the independent variable and differ from each other by an equal interval

Question 5

Log Dilutions

Answer 5

Often used in microbiology to estimate concentration or density of cells in a stock culture and differ by a constant proportion

Question 6

Buffer

Answer 6

Solutions that can resist changes of pH even when acid or alkali is added allowing the pH of a reaction mixture to be kept constant

Question 7

Centrifugation

Answer 7

Used to separate components of a suspension that have a different density

Question 8

Paper/Thin Layer Chromatography

Answer 8

Used to separate different substances such as amino acids and sugars.

Question 9

Affinity Chromatography

Answer 9

Used to separate target proteins from a mixture of proteins

Question 10

Gel Electrophoresis

Answer 10

Charged molecules such as proteins or nucleic acids, move through an electric field applied to a buffered gel matrix

Question 11

Native PAGE

Answer 11

Don’t denature the molecules being separated so the separation is by shape, size and charge.

Question 12

SDS-PAGE

Answer 12

Denatures molecules passing through it, giving all molecules an equally negative charge, meaning they can be separated by size alone.

Question 13

Isoelectric Point (4 points)

Answer 13

• pH at which a protein is electrically neutral, with surface charges that are balanced.
• pHs below IEP, net charges positive
• pHs above IEP, net charges negative
• At IEP, the protein loses solubility in water and starts to solidify and precipitate out of solution.

Question 14

What are immunoassay techniques used for?

Answer 14

To detect and identify specific proteins

Question 15

Monoclonal Antibodies

Answer 15

Stocks of antibodies with the same specificity

Question 16

When is Western Blotting used?

Answer 16

After SDS-PAGE

Question 17

Western Blotting

Answer 17

Separated proteins from gel transferred to solid medium which can then be identified using specific antibodies that have reporter enzymes attached

Question 18

Bright Field Microscopy

Answer 18

Used to examine whole organisms, parts of organisms, thin sections of dissected tissue or individual cells

Question 19

Fluorescence Microscopy

Answer 19

Uses UV light to detect specific fluorescent stains, which bind to and visualise certain molecules within cells or tissues.

Question 20

Aseptic Technique

Answer 20

Eliminates unwanted microbial contaminants when culturing microorganisms or cells. It involves the sterilisation of equipment and culture media by heat or chemicals.

Question 21

Vital Staining

Answer 21

Required to identify and count viable cells because the stain can distinguish between cells that are alive or dead.

Question 22

Primary Cell Lines

Answer 22

Can divide a limited number of times

Question 23

Tumour Cell Lines

Answer 23

Can perform unlimited divisions

Question 24

Alternative to Vital Staining

Answer 24

Colony Count

Question 25

Colony Count

Answer 25

Alternative to Vital Staining