Laboratory Techniques

Question 1

Hazards in the lab include…

Answer 1

toxic or corrosive chemicals, heat or flammable substances, pathogenic organisms and mechanical equipment

Question 2

What is risk?

Answer 2

the likelihood of harm arising from exposure to a hazard

Question 3

What do control measures include?

Answer 3

appropriate handling techniques, protective clothing and equipment and aseptic techniques

Question 4

Dilutions in a linear dilution series differ by…

Answer 4

an equal interval

Question 5

dilutions in a log dilution series differ by…

Answer 5

a constant proportion

Question 6

Addition of acid or alkali has very small effects on the pH of a buffer, allowing…

Answer 6

the pH of a reaction mixture to be kept constant

Question 7

Absorbance is used to determine..

Answer 7

the concentration of a COLOURED SOLUTION using suitable wavelength filters

Question 8

Percentage transmission is used to…

Answer 8

determine turbidity

Question 9

What can percentage transmission be used to estimate?

Answer 9

the number of cells in suspension

Question 10

What do centrifuges do?

Answer 10

separate substances of differing density

Question 11

What can paper and thin layer chromatography be used for?

Answer 11

separating different substances such as amino acids and sugars

Question 12

More dense components settle in the…

Answer 12

pellet

Question 13

less dense components remain in the…

Answer 13

supernatant

Question 14

The speed that each solute travels along the chromatogram depends on…

Answer 14

its differing solubility in the solvent used

Question 15

What happens in gel electrophoresis?

Answer 15

charged macromolecules move through an electric field applied to a gel matrix

Question 16

Gel electrophoresis separates proteins based on their

Answer 16

shape, size and charge

Question 17

SDS separates proteins by…

Answer 17

size alone

Question 18

Why don’t native gels denature the molecule?

Answer 18

so that separation is by size, shape and charge

Question 19

SDS PAGE gives all the molecules an equally…..

Answer 19

negative charge and denatures them

Question 20

Proteins can be separated from a mixture using their…

Answer 20

isoelectric points (IEPs)

Question 21

What is the IEP?

Answer 21

the pH at which a soluble protein has no net charge and will precipitate out of solution

Question 22

If the solution is buffered to a specific pH, only the protein(s) that….

Answer 22

have an IEP of that pH will precipitate

Question 23

Proteins can also be separated using their IEPS in a technique called…

Answer 23

electrophoresis

Question 24

soluble proteins can be separated using an electric field and a

Answer 24

pH gradient

Question 25

A protein stops migrating through the gel at it’s IEP in the pH gradient because…

Answer 25

it has no net charge

Question 26

What are immunoassay techniques used for?

Answer 26

Used to detect and identify specific proteins

Question 27

What do immunassay techniques use?

Answer 27

monoclonal antibodies

Question 28

What are monoclonal antibodies?

Answer 28

stocks of antibodies with the same specificity

Question 29

What is western blotting?

Answer 29

A technique used after SDS-PAGE electrophoresis

Question 30

Describe the process of western blotting

Answer 30

The separated 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 31

How can separated proteins be identified?

Answer 31

By using specific antibodies that have reporter enzymes attached

Question 32

What is the ‘label’?

Answer 32

The label is often a reporter enzyme producing a colour change, but chemiluminescence, fluorescence and other reporters can be used

Question 33

In some cases the assay uses a specific antigen to detect the presence of ___________

Answer 33

antibodies

Question 34

What is Bright-field microscopy commonly used to observe?

Answer 34

Whole organisms, parts of organisms, thin sections of dissected tissue or individual cells

Question 35

What is fluorescence microscopy?

Answer 35

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

Question 36

What is the purpose of aseptic technique

Answer 36

eliminates unwanted contaminants when culturing micro-organisms or cells

Question 37

How can a microbial culture be started?

Answer 37

Using an inoculum of microbial cell;s on an agar medium, or in a broth with suitable nutrients

Question 38

How are animal cells grown?

Answer 38

in a medium containing growth factors from serum

Question 39

In culture, primary cell lines can divide a __________ number of times

Answer 39

limited

Question 40

tumour cell lines can perform ____________ divisions

Answer 40

unlimited

Question 41

Plating out of a liquid microbial culture on solid media allows…

Answer 41

the number of colony-forming units to be counted and the density of cells in the culture to be estimated

Question 42

_______ ___________ is often needed to achieve a suitable colony count

Answer 42

serial dilution

Question 43

What do haemocytometers do?

Answer 43

estimate cell numbers in a liquid culture

Question 44

What is vital staining?

Answer 44

Vital staining is required to identify and count viable cells

Question 45

What does asceptic technique involve?

Answer 45

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

Question 46

Many culture media exist that promote…

Answer 46

the growth of specific types of cells and microbes

Question 47

What are growth factors?

Answer 47

Proteins that promote cell growth and proliferation

Question 48

Growth factors are essential for the…

Answer 48

culture of most animal cells