1.1

Question 1

hazard

Answer 1

a factor or object that can cause harm upon exposure.
E.g. Pathogenic organisms, toxic and corrosive chemicals, heat and flammable substances, equipment.

Question 2

risk

Answer 2

the likelihood of harm arising from exposure to a hazard

Question 3

risk assessment

Answer 3

Involves identifying control measures to minimise risk

Question 4

control measures

Answer 4

include using appropriate handling techniques, PPE and aseptic technique

Question 5

pathogenic organism

Answer 5

an organism that can cause disease

Question 6

aseptic technique

Answer 6

technique used to reduce contamination

Question 7

autopipette

Answer 7

used to measure very small volumes of liquid accurately

Question 8

burette

Answer 8

used to dispense precise volumes of liquid reagents

Question 9

linar dilution

Answer 9

dilutions of a solution which differ by a constant proportion

Question 10

standard curve

Answer 10

to determine the concentration of an unknown solution

Question 11

buffer

Answer 11

used to control pH, allows pH of a solution to be kept constant

Question 12

colorimeter

Answer 12

used to quantify the concentration (absorbance) or turbidity (uses transmission) of a solution, use blank to calibrate

Question 13

spectrophotometer

Answer 13

used to determine the spectra reflectance at each wavelength, more complex analysis than colorimeter

Question 14

centrifugation

Answer 14

used to separate substances of differing density

Question 15

supernatant

Answer 15

a solution of lower density materials that is formed at the top of an Eppendorf tube after centrifugation

Question 16

pellet

Answer 16

higher density materials that form at the bottom of an Eppendorf tube after centrifugation

Question 17

chromatography

Answer 17

a separation technique used to separate the components of a mixture (amino acids, sugars, proteins).

Question 18

paper chromatography

Answer 18

to separate pigments in a leaf, uses polar cellulose fibres, polar components bind, non-polar don’t bind as readily and travel further.

Question 19

thin layer chromatography

Answer 19

to separate different substance such as amino acids and sugars but stationary phase is a strip of absorbent material (e.g. silica gel)

Question 20

mobile phase

Answer 20

the mixture to be separated during chromatography is dissolved into this fluid.

Question 21

stationary phase

Answer 21

components of mixture are separated as they move through this, changes depending on chromatography type.

Question 22

affinity chromatography

Answer 22

used to separate proteins

Question 23

affinity

Answer 23

the degree to which a substance is attracted and tends to bind to another

Question 24

What are the basics of gel electrophoresis (PAGE)

Answer 24

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

Question 25

What is native PAGE?

Answer 25

do not denature the molecules being separated - they preserve structure and function
separation is by shape, size and charge

Question 26

What is SDS-PAGE?

Answer 26

contain sodium dodecyl sulfate which denatures molecules passing through
gives molecules a negative charge, separating proteins by size alone
simple to carry out but structure and function of protein is lost

Question 27

What is the isolelectric (IEP) point?

Answer 27

the pH value at which these proteins are electrically neutral, with surface charges that are balanced
pH below IEP = +
pH above IEP = -
at IEP the protein loses water solubility and precipitates out of solution

Question 28

What are imunoassay techniques?

Answer 28

used to detect/identify specific proteins, use antibodies called monoclonal antibodies which are linked to chemical ‘label’ of an enzyme that changes colour or that shows chemiluminescence, fluorescence or radioactivity
specific antigens bind and colour change occurs

Question 29

What is western blotting?

Answer 29

used after SDS-PAGE, the separated proteins are blotted to a solid medium and dried
proteins labelled using antibodies then antibody with ‘label’ is added so that it is visible to the eye

Question 30

What is bright field microscopy?

Answer 30

examines whole organisms, parts of organisms, thin dissected tissue or cells

Question 31

What is fluorescence microscopy?

Answer 31

uses UV light to detect specific fluorescent stains which bind to and visualise certain molecules or structures within cell or tissues

Question 32

Aseptic technique

Answer 32

eliminates unwanted microbial contaminants when culturing micro-organisms or cells
involves sterilisation of equipment and culture media by heat or chemical means

Question 33

How can a microbial culture be started?

Answer 33

using an inoculum of microbial cells on an agar medium or in a broth with suitable nutrients

Question 34

What are animal cells grown in?

Answer 34

medium containing serum which contains growth factors

Question 35

What are growth factors?

Answer 35

proteins that promote growth and proliferation

Question 36

Why would you want to plate a microbial culture?

Answer 36

plating of liquid culture onto solid media allow number of colony-forming units to be counted and density of cells estimated
serial dilution often needed to achieve

Question 37

What are haemocytometers?

Answer 37

microscopic grids used to estimate cell numbers in a liquid culutre
vital staining needed

Question 38

What is vital staining?

Answer 38

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