1.1

Question 1

Hazard

Answer 1

Something that can cause harm

Corrosive chemicals

Question 2

Risk

Answer 2

Risk is the likelihood of harm arising from exposure to a hazard

Question 3

Control measures to reduce risks

Answer 3

Wearing PPE: safety goggles, protective gloves

Using appropriate handling techniques

Using aseptic techniques to minimise microbial contamination

Question 4

Colorimeter

Answer 4

A Colorimeter is used to measure the concentration of a pigment in a solution, turbidity of a liquid, or the density of cells in a culture.

Question 5

How does a colorimeter work?

Answer 5

It illuminates a small sample of the test substance, held in a small transparent cuvette, using a coloured light source.

Question 6

What value does a colorimeters display?

Answer 6

Absorbance (used to determine the concentration of a colour solution)

Percentage transmission (used to determine turbidity such as cells in suspension)

Question 7

Buffers

Answer 7

A buffer keeps the pH of a solution constant by taking a protons that are released during reactions, or by releasing protons when they are consumed by reactions

Question 8

Centrifugation process

Answer 8

Centrifugation is the process by which a centrifuge is used to separate components of a complex mixture by the density.

Denser substances form a pellet at the bottom and the supernatant (liquid) of different density and solubility sits on top of the pellet.

Question 9

Paper chromatography

Answer 9

Paper chromatography can be used to separate and identify amino acids

Question 10

Thin-layer chromatography (TLC)

Answer 10

(Similar to paper chromatography)

TLC uses a sheet of glass, plastic or aluminium foil, which is coated in a thin layer of absorbent material.

TLC tends to produce more useful chromatographs than paper chromatography as they are easier to analyse

Question 11

What is Affinity chromatography used for?

Answer 11

Affinity chromatography is used to separate target proteins from a mixture.

Question 12

How does affinity chromatography work?

Answer 12

Affinity chromatography separates biochemical mixtures based on a high affinity between proteins.

(E.g. such as affinity enzyme and substrate)

Question 13

Gel electrophoresis

Answer 13

Gel electrophoresis separates proteins and nucleic acids based upon their charge or size

Question 14

How does gel electrophoresis work?

Answer 14

The gel is mounted between two buffer Chambers. An electric field is applied which forces the migration of protein into and through the gel. The smaller molecules travel more rapidly than the larger molecules.

Question 15

Types of gel electrophoresis

Answer 15

Native – gel electrophoresis

SDS – PAGE electrophoresis

Question 16

How does Native gel electrophoresis separate proteins

Answer 16

Native gels do not denature the molecule so separate proteins by their shape, size and charge

Question 17

SDS-PAGE

Answer 17

SDS-PAGE gives all the proteins an equally negative charge and denatures them, separating proteins by size alone.

Question 18

How can proteins be separated using their pH?

Answer 18

Proteins can be separated from the mixture using their isoelectric points

Question 19

What is the IEP of a protein?

Answer 19

The isoelectric point of a protein is the pH at which it has no net charge. At this pH, the protein will precipitate out of solution

Question 20

IEP and buffered solutions

Answer 20

If the solution is buffered to a specific pH, only the proteins that have an IEP of that pH will precipitate out of solution

Question 21

How can soluble proteins be separated and when can do these proteins stop moving through the gel?

Answer 21

soluble proteins can be separating using an electric field and a pH gradient (IEP). A protein stops migrating through the gel at its IEP in the pH gradient because it has no net charge

Question 22

What is a Serum with different antibodies called and how can they be removed?

Answer 22

A serum made with many different antibodies against an antigen is described as polyclonal. The antibodies can be removed from the blood by centrifugation

Question 23

Immunoassay techniques uses

Answer 23

Immunoassay techniques are used to detect and identify specific proteins

Question 24

What do amino acid techniques use?

Answer 24

Immunoassay techniques use stocks of antibodies with the same specificity, known as monoclonal antibodies

Question 25

Chemical label

Answer 25

An antibody specific to the protein antigen is linked to a chemical ‘label’.

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

Question 26

Western blotting technique

Answer 26

Used after SDS-PAGE

THE SEPARATED PROTEINS FROM THE GEL ARE TRANSFERRED (BLOTTED) ON TO A SOLID MEDIUM which is probed for the protein of interest using a specific antibody that is linked to a detectable label.

THE PROTEINS CAN BE IDENTIFIED USING SPECIFIC ANTIBODIES THAT HAVE REPORTER ENZYMES ATTACHED

Question 27

Brightfield microscopy

Answer 27

Brightfield microscopy is commonly used to absorb whole organisms, parts of organisms, thin sections of dissected tissue, or individual cells

Question 28

Fluorescence microscopy

Answer 28

Fluorescence microscopy uses specific fluorescent labels to bind to and visualise certain molecules or structures within cells or tissues

Question 29

What do Aseptic technique do?

Answer 29

Aseptic techniques eliminate unwanted microbial contaminants when culturing microorganisms or cells

Question 30

What does Aseptic techniques involve?

Answer 30

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

Question 31

How can a Microbial culture be started

Answer 31

Microbio culture can be started using an inoculum of microbial cells on an agar medium or in a broth with suitable nutrients

Question 32

What is cell culture?

Answer 32

Cell culture is the ability to grow cells in an artificial laboratory environment

Question 33

Where animal cells grown

Answer 33

Animal cells are grown in medium containing growth factors provided by animal serum

Question 34

What are growth factors?

Answer 34

Growth factors are proteins that promotes cell growth and proliferation. Growth factors are essential for the culture of most animal cells.

Question 35

What is a cell line?

Answer 35

A cell line is a genetically uniform cell culture developed from a single cell

Question 36

Primary cell lines VS tumour cell lines

Answer 36

In culture, primary cell lines can divide a limited number of times, whereas tumour cell lines can perform, unlimited divisions (immortal).

Question 37

Plating out of a liquid microbial culture

Answer 37

Plating out of a liquid microbial culture on solid media allows the number of colony-forming units to be counted and the density of cells in the culture estimated

Question 38

What is often needed to achieve a suitable colony count?

Answer 38

Serial dilution

Question 39

What does a haemocytometer do

Answer 39

A haemocytometer allows an estimate of the number of cells in a culture to be made

Vital staining require to identify and count viable cells

Question 40

Haemocytometer disadvantages

Answer 40

Unless stained, dead cells are not distinguished from live cells

Time-consuming

Cells may come together

Only provides an estimate for a larger population