KA 1

Question 1

What can present a hazard?

Answer 1

Substances, organisms, and equipment in a laboratory

Question 2

Hazards in the lab include…

Answer 2

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

Question 3

Hazard, risk, and control of risk in the lab by…

Answer 3

Risk assessment

Question 4

What is risk?

Answer 4

The likelihood of harm arising from exposure to a hazard.

Question 5

Risk assessment involves…

Answer 5

Identifying control measures to minimise the risk.

Question 6

Control measures for risks include…

Answer 6

Using appropriate handling techniques, protective clothing and equipment, and aseptic technique.

Question 7

Dilutions in a linear dilution series differ by?

Answer 7

An equal interval, for example 0·1, 0·2, 0·3 and so on.

Question 8

Dilutions in a log dilution series differ by a?

Answer 8

Constant proportion, for example 10-1 , 10-2 , 10-3 and so on.

Question 9

How can you determine an unknown?

Answer 9

Production of a standard curve

Question 10

Plotting measured values for known concentrations to produce a line or curve allows?

Answer 10

The concentration of an unknown to be determined from the standard curve.

Question 11

Use of buffers to control? Why is this important?

Answer 11

pH Addition of acid or alkali has very small effects on the pH of a buffer, allowing the pH of a reaction mixture to be kept constant.

Question 12

Method and uses of a colorimeter to? And how/why do you do these?

Answer 12

Quantify concentration and turbidity
Calibration with appropriate blank as a baseline; use of absorbance to determine concentration of a coloured solution using suitable wavelength filters; use of percentage transmission to determine turbidity, such as cells in suspension.

Question 13

Use a colorimeter or spectrophotometer to calibrate a?

Answer 13

Known solution and determine an unknown using, for example, Bradford protein assay.

Question 14

Use of centrifuge to separate substances of? How?

Answer 14

Differing density More dense components settle in the pellet; less dense components remain in the supernatant.

Question 15

Paper and thin layer chromatography can be used for…

Answer 15

Separating different substances such as amino acids and sugars

Question 16

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

Answer 16

Its differing solubility in the solvent used. Details of how to carry out these procedures are not required.

Question 17

A solid matrix or gel column is created with?

Answer 17

Specific molecules bound to the matrix or gel. Soluble, target proteins in a mixture, with a high affinity for these molecules, become attached to them as the mixture passes down the column.

Question 18

Other non-target molecules with a weaker affinity are…

Answer 18

Washed out.

Question 19

Charged macromolecules move through an electric field applied to a?

Answer 19

Gel matrix

Question 20

Use protein electrophoresis to identify?

Answer 20

Different muscle proteins.

Question 21

Native gels separate proteins by their?

Answer 21

Shape, size and charge

Question 22

Native gels do not… why?

Answer 22

Denature the molecule so that separation is by shape, size and charge.

Question 23

SDS–PAGE separates proteins by?

Answer 23

Size alone

Question 24

SDS–PAGE gives all the molecules an equally? Doing what?

Answer 24

Negative charge and denatures them, separating proteins by size alone.

Question 25

Proteins can be separated from a mixture using their…

Answer 25

Isoelectric points (IEPs)

Question 26

If the solution is buffered to a specific pH what will happen?

Answer 26

Only the protein(s) that have an IEP of that pH will precipitate IEP is the pH at which a soluble protein has no net charge and will precipitate out of solution.

Question 27

Proteins can also be separated using their?

Answer 27

IEPs in electrophoresis

Question 28

Soluble proteins can be separated using?

Answer 28

An electric field and a pH gradient.

Question 29

A protein stops migrating through the gel at its…Because?

Answer 29

EP in the pH gradient because it has no net charge.

Question 30

Immunoassay techniques are used to detect and identify?

Answer 30

Specific proteins. These techniques use stocks of antibodies with the same specificity, known as monoclonal antibodies.

Question 31

An antibody specific to the protein antigen is linked to a? What is this often?

Answer 31

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

Question 32

In some cases the assay uses a specific?

Answer 32

Antigen to detect the presence of antibodies.

Question 33

Use the ELISA technique to identify the presence of?

Answer 33

Specific antigens.

Question 34

Western blotting is a technique used after?

Answer 34

SDS–PAGE electrophoresis. The separated proteins from the gel are transferred (blotted) onto a solid medium

Question 35

The proteins can be identified using? What is attached?

Answer 35

Specific antibodies that have reporter enzymes attached

Question 36

Bright-field microscopy is commonly used to observe?

Answer 36

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

Question 37

Fluorescence microscopy uses…

Answer 37

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

Question 38

Aseptic technique eliminates unwanted? When…

Answer 38

Microbial contaminants when culturing microorganisms or cells

Question 39

Aseptic technique involves the?

Answer 39

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

Question 40

A microbial culture can be started using an?

Answer 40

Inoculum of microbial cells on an agar medium, or in a broth with suitable nutrients

Question 41

Many culture media exist that promote?

Answer 41

Growth of specific types of cells and microbes. Culture bacterial, yeast, and algal cells using aseptic technique.

Question 42

Animal cells are grown in medium containing?

Answer 42

Growth factors from serum In culture

Question 43

Primary cell lines can divide? What about tumour cell lines?

Answer 43

A limited number of times, whereas tumour cells lines can perform unlimited divisions

Question 44

Plating out of a liquid microbial culture on solid media allows the number of?

Answer 44

Colonyforming units to be counted and the density of cells in the culture estimated

Question 45

Serial dilution is often needed to achieve?

Answer 45

A suitable colony count

Question 46

Growth factors are?

Answer 46

Proteins that promote cell growth and proliferation.

Question 47

Growth factors are essential for?

Answer 47

The culture of most animal cells.

Question 48

Method and use of haemocytometer to estimate?

Answer 48

Cell numbers in a liquid culture

Question 49

Vital staining is required to?

Answer 49

Identify and count viable cells

Question 50

Use a haemocytometer to make an?

Answer 50

Estimate of cell count