1.1 LAB TECHNIQUES FOR BIOLOGISTS

Question 1

What can chemicals and organisms be?

Answer 1

Intrinsically hazardous

Question 2

What can chemicals and organisms pose risk to?

Answer 2

People, other organisms, environment

Question 3

Give an example of a physical control measure.

Answer 3

Personal protective equipment (PPE)

Question 4

Give an example of a biological control measure.

Answer 4

Using a more suitable strain of microorgansim

Question 5

What is a linear dilution series?

Answer 5

A range of dilutions which differ by an equal interval

Question 6

How do you perform a linear dilution series?

Answer 6

Add different volumes of stock solution to different volumes of solvent

Question 7

What is a logarithmic dilution series?

Answer 7

A range of dilutions which differ by a constant proportion

Question 8

How do you perform a logarithmic dilution series?

Answer 8

Add same volumes of stock to same volumes of solvent using each solution as stock for subsequent dilution

Question 9

What is the result of an error being made while making stock?

Answer 9

Errors are compounded in any further dilutions made

Question 10

What is used to determine the concentration of an unknown solution?

Answer 10

A standard curve for determination of an unkown

Question 11

What is a ‘standard curve’?

Answer 11

A series of ‘standards’ of known concentrations are measured and depicted on a graph

Question 12

What is a pH buffer?

Answer 12

A solution whose pH changes very little when either a small amount of acid or base is added

Question 13

What is used to measure pH?

Answer 13

A meter or indicator

Question 14

Name 5 tools used to measure liquid volumes.

Answer 14

Cylinders, pipettes, burettes, autopipettors, syringes

Question 15

What is a colorimeter used for?

Answer 15

Quantifying the concentration of a pigmented compound

Question 16

What can substances be separated by?

Answer 16

Solubility, size, shape, charge

Question 17

What is centrifugation used to separate?

Answer 17

Pellet and supernatant

Question 18

What is the pellet?

Answer 18

Largest and densest materials at bottom of tube

Question 19

What is the supernatant?

Answer 19

The liquid remaining above the pellet

Question 20

What separates pellets and supernatants?

Answer 20

Size and density

Question 21

What is the purpose of chromatography?

Answer 21

To separate the components of a mixture - amino acids and proteins

Question 22

Name the three types of chromatography.

Answer 22

Paper, thin layer, affinity

Question 23

How does paper chromatography separate components?

Answer 23

Solvent is drawn up a piece of chromatography paper

Question 24

How does thin layer chromatography separate components?

Answer 24

Using a TLC strip

Question 25

How does affinity chromatography separate components?

Answer 25

Relies on binding interactions between protein of interest and a ligand

Question 26

What does electrophoresis separate?

Answer 26

Proteins

Question 27

How does electrophoresis separate proteins?

Answer 27

Uses a current flowing through a buffer

Question 28

What factors affect protein migration in a gel?

Answer 28

Size and charge

Question 29

How can proteins be separated by their pH?

Answer 29

They are separated at their iso-electric point

Question 30

What happens at a protein's iso-electric point?

Answer 30

Has overall neutral charge and precipitates out solution

Question 31

What can antibody techniques be used for?

Answer 31

Detection and identification of specific proteins

Question 32

What proteins are involved in immunoassay techniques?

Answer 32

Antibodies linked to reporter enzymes

Question 33

What do antibodies linked to reporter enzymes in immunoassay techniques do?

Answer 33

Cause a colour change in presence of a specific antigen

Question 34

What are antibodies also involved in?

Answer 34

Protein blotting and immunohistochemical staining of tissue

Question 35

What is the first stage of protein blotting?

Answer 35

Proteins separated by electrophoresis and transferred to a membrane

Question 36

What happens after the proteins are transferred to a membrane in protein blotting?

Answer 36

Membrane is probed for protein of interest using an antibody linked to a detectable label

Question 37

How does the label indicate the presence of a target protein in protein blotting?

Answer 37

May be linked to a reporter enzyme which causes a detectable colour change in protein's presence

Question 38

What is immunohistochemical staining used for?

Answer 38

To visualise distribution of specific cellular components in live cells

Question 39

How are monoclonal antibodies produced?

Answer 39

Using hybridomas

Question 40

How are hybridomas produced?

Answer 40

Fusing a B lymphocyte with a myeloma cell

Question 41

What is used to fuse a B lymphocyte with a myeloma cell?

Answer 41

Polyethylene glycol (PEG)

Question 42

What is bright field microscopy used for?

Answer 42

Examination of whole/parts of organisms or thin sections of dissected tissue

Question 43

How does bright field microscopy work?

Answer 43

Light transmitted through a specimen to an objective lens (for magnification) and then to an eyepiece

Question 44

What does fluorescence microscopy enable?

Answer 44

Visualisation of particular protein structures

Question 45

How does fluorescence microscopy work?

Answer 45

Fluorescent markers added to specific protein structures, cells placed on a slide, structures visualised through fluorescence microscope

Question 46

What are aseptic techniques?

Answer 46

Practices and procedures used to prevent contamination from pathogens

Question 47

Give two examples of aseptic techniques.

Answer 47

Sterilisation of containers, equipment and materials, disinfection of working area

Question 48

What is inoculum?

Answer 48

Cells that are used to inoculate culture media

Question 49

What are explants?

Answer 49

Small pieces of tissue

Question 50

What are haemocytometers used for?

Answer 50

Estimation of total cell counts

Question 51

What is vital staining used for?

Answer 51

Estimation of viable cell counts

Question 52

What does culture media contain?

Answer 52

Requirements of the cells

Question 53

What does complex culture media contain?

Answer 53

Factors from serum for animal cell lines

Question 54

Compare the lifetime of primary cell lines vs cancer cell lines.

Answer 54

Primary cell lines have a limited lifetime whereas cancer cell lines grow and divide indefinitely

Question 55

What are growth regulators used for in plant tissue culture?

Answer 55

Induction of embryogenesis to generate whole new embryonic plants