Laboratory Techniques Flashcards

1
Q

Hazards in the lab include…

A

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

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2
Q

What is risk?

A

the likelihood of harm arising from exposure to a hazard

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3
Q

What do control measures include?

A

appropriate handling techniques, protective clothing and equipment and aseptic techniques

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4
Q

Dilutions in a linear dilution series differ by…

A

an equal interval

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5
Q

dilutions in a log dilution series differ by…

A

a constant proportion

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6
Q

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

A

the pH of a reaction mixture to be kept constant

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7
Q

Absorbance is used to determine..

A

the concentration of a COLOURED SOLUTION using suitable wavelength filters

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8
Q

Percentage transmission is used to…

A

determine turbidity

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9
Q

What can percentage transmission be used to estimate?

A

the number of cells in suspension

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10
Q

What do centrifuges do?

A

separate substances of differing density

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11
Q

What can paper and thin layer chromatography be used for?

A

separating different substances such as amino acids and sugars

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12
Q

More dense components settle in the…

A

pellet

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13
Q

less dense components remain in the…

A

supernatant

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14
Q

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

A

its differing solubility in the solvent used

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15
Q

What happens in gel electrophoresis?

A

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

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16
Q

Gel electrophoresis separates proteins based on their

A

shape, size and charge

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17
Q

SDS separates proteins by…

A

size alone

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18
Q

Why don’t native gels denature the molecule?

A

so that separation is by size, shape and charge

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19
Q

SDS PAGE gives all the molecules an equally…..

A

negative charge and denatures them

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20
Q

Proteins can be separated from a mixture using their…

A

isoelectric points (IEPs)

21
Q

What is the IEP?

A

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

22
Q

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

A

have an IEP of that pH will precipitate

23
Q

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

A

electrophoresis

24
Q

soluble proteins can be separated using an electric field and a

A

pH gradient

25
A protein stops migrating through the gel at it's IEP in the pH gradient because...
it has no net charge
26
What are immunoassay techniques used for?
Used to detect and identify specific proteins
27
What do immunassay techniques use?
monoclonal antibodies
28
What are monoclonal antibodies?
stocks of antibodies with the same specificity
29
What is western blotting?
A technique used after SDS-PAGE electrophoresis
30
Describe the process of western blotting
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
31
How can separated proteins be identified?
By using specific antibodies that have reporter enzymes attached
32
What is the 'label'?
The label is often a reporter enzyme producing a colour change, but chemiluminescence, fluorescence and other reporters can be used
33
In some cases the assay uses a specific antigen to detect the presence of ___________
antibodies
34
What is Bright-field microscopy commonly used to observe?
Whole organisms, parts of organisms, thin sections of dissected tissue or individual cells
35
What is fluorescence microscopy?
Uses specific fluorescent labels to bind to and visualise certain molecules or structures within cells or tissues
36
What is the purpose of aseptic technique
eliminates unwanted contaminants when culturing micro-organisms or cells
37
How can a microbial culture be started?
Using an inoculum of microbial cell;s on an agar medium, or in a broth with suitable nutrients
38
How are animal cells grown?
in a medium containing growth factors from serum
39
In culture, primary cell lines can divide a __________ number of times
limited
40
tumour cell lines can perform ____________ divisions
unlimited
41
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 to be estimated
42
_______ ___________ is often needed to achieve a suitable colony count
serial dilution
43
What do haemocytometers do?
estimate cell numbers in a liquid culture
44
What is vital staining?
Vital staining is required to identify and count viable cells
45
What does asceptic technique involve?
The sterilisation of equipment and culture of media by heat or chemical means and subsequent exclusion of microbial contaminants
46
Many culture media exist that promote...
the growth of specific types of cells and microbes
47
What are growth factors?
Proteins that promote cell growth and proliferation
48
Growth factors are essential for the...
culture of most animal cells