UNIT 1 - KA1 Flashcards

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1
Q

What is a hazard

A

A hazard is a source of potential harm

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2
Q

What are hazards in the lab (4)

A

toxic, or corrosive chemicals
heat or flammable substances
Pathogenic organisms
Mechanical equipment

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3
Q

What is a risk

A

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

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4
Q

Risk assessment

A

Risk assessment involves identifying control measures to minimise the risk

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5
Q

Control measures

A

Appropriate handling techniques
Protective clothing and equipment
Aseptic technique

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6
Q

What is a ph buffer

A

A ph buffer is a solution whose pH changes very little when a small amount of acid or base is added to it

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7
Q

How do buffers work

A

Buffers work by allowing the addition of hydrogen or hydroxide ions without affecting the pH of the solution

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8
Q

Why are buffer solutions used

A

Buffer solutions are used as a means of keeping ph at a nearly constant value

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9
Q

What is the application of centrifugation

A

Separation according to density

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10
Q

How does a centrifuge separate substances of differing density

A

More dense compounds settle in the pallet whereas less dense components remain in the supernatant

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11
Q

What are the names given to the solid and liquid in a centrifuge tube

A

The solid found at the base of the tube is called the pellet and the liquid the supernatant

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12
Q

What are linear dilutions used for

A

Used if you need a sample over a reasonably small range

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13
Q

How do dilutions in a linear dilution series differ

A

Dilutions in a linear dilution series differ by an equal interval for example 0.1, 0.2 ,0.3 and so on.

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14
Q

What are serial (log dilutions) used for

A

Where dilution is needed across a wide range a serial dilution produces sampled which differ from the next by an order of magnitude each time

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15
Q

How do dilutions in a log dilution series differ

A

Dilutions in a log dilution series differ by a constant proportion, eg 10^-1 , 10^-2 , 10^-3 and so on

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16
Q

How does the production of a standard curve determine an unknown

A

Plotting measured values for known concentrations to produce a line or a curve allows the concentration of an unknown to be determined from the standard curve

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17
Q

What can paper and thin layer chromatography be used for

A

Paper and thin layer chromatography can be used for separating different substances such as amino acids and sugars

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18
Q

What does the speed at which the solute travels through the chromatogram depend on

A

The speed that each solute travels along the chromatogram depends on its differing solubility in the solvent used

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19
Q

How is a solid matrix or gel column created

A

A solid matrix or gel column is created with specific molecules bound to the matrix or gel

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20
Q

What happens to soluble target proteins in affinity chromatography

A

Soluble target proteins in a mixture with high affinity for these molecules become attached to them as the mixture passes down the column

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21
Q

What happens to non target molecules in affinity chromatography

A

Other non - target molecules with a weaker affinity are washed out

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22
Q

What is the process of electrophoresis

A

Electrophoresis is the process of moving charged molecules in solution by applying an electric field across the mixture

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23
Q

What three factors determine the speed at which molecules move in protein electrophoresis

A

The molecules move with a speed dependant on their charge, shape size and so they can be separated from other molecules using this technique

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24
Q

What is the gel in gel electrophoresis made of

A

The gel is made of agarose

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25
Q

How is the tank set up in gel electrophoresis

A

The tank is set up with a positive and negative terminal and an electric current is applied

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26
Q

Where do the fragments move towards in gel electrophoresis

A

The fragments move towards the electrode which is of the opposite charge to the fragments

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27
Q

Where do smaller and larger fragments move to

A

Smaller fragments move more Quickly (do not get tangled on the agarose protein strands) than the larger fragments.

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28
Q

How do native gels separate proteins

A

Native gels separate proteins by their shape, size and charge

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29
Q

How do native gels separate by shape size and charge

A

Native gels do not denature the molecule so that separation is by shape, size and charge.

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30
Q

How does SDS page separate proteins

A

SDS page gives all the molecules an equally negative charge and denatures them separating proteins by size alone

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31
Q

What is the iso electric point of a soluble protein

A

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

32
Q

What happens to proteins if a solution is buffered to a specific pH

A

If the solution is buffered to a specific pH, only the protein(s) that have an IEP of that pH will precipitate

33
Q

What is another way soluble proteins can be separated

A

Soluble proteins can be separated using an electric field and a pH gradient.

34
Q

When does a protein stop migrating through the gel

A

A protein stops migrating through the gel at its IEP in the pH gradient because it has no net charge.

35
Q

What are antibodies

A

Antibodies are y shaped globular proteins produced by B lymphocytes as part of the specific immune response

36
Q

What types of cells produce antibodies

A

Each b lymphocytes produces one specific antibody that binds to one specific type of antigen

37
Q

What does the binding of antibody’s and antigens render

A

The binding renders the antigen harmless and promotes destruction of invading pathogens

38
Q

What are immunoassay techniques used for

A

Immunoassay techniques are used to detect and identify specific proteins

39
Q

What type of antibodies do immunoassay techniques use

A

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

40
Q

What should any antibody in an immunoassay be linked to

A

Any antibody used in an immunoassay must be linked to a detective label to allow scientists to detect when binding has occurred

41
Q

What is a polyclonal antibody

A

Many different antibodies will have formed to different parts of the same antigen. Each antibody is made by a single B lymphocyte clone. A serum made in this way with many different antibodies against the same antigen is described as polyclonal

42
Q

What are monoclonal antibodies

A

These are antibodies which are identical to each other and will bind to exactly the same feature (eg same protein) of the antigen

43
Q

How should b lymphocytes be grown in relation to monoclonal antibodies

A

A single line of B lymphocytes must be grown each secreting the same specific antibody

44
Q

What forms are the detectable label in

A

These labels may be in the form of a reporter enzyme which causes a colour change in the presence of a specific antigen. Chemiluminescence, fluorescence and other reporters can also be used

45
Q

In some cases what could the assay do

A

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

46
Q

What is an immunoassay

A

An immunoassay is a biochemical test that measures the presence of concentration of a macromolecule in a solution through the use of an antibody

47
Q

What is one of the main types of immunoassay

A

One of the main types of immunoassay carried out is the Elisa test

48
Q

What happens in the Elisa test

A

In this test antibodies linked to reporter enzymes cause a colour change in the presence of a specific antigen

49
Q

Draw a label of detection of a protein or antibody

A

Check jotter

50
Q

What is immunohistochemical staining

A

Labelled antibodies are also used for immunohistochemical staining. Where an antibody to a particular antigen can be used to identify tissue proteins

51
Q

What is western blotting

A

Western blotting is a technique used after SDS page electrophoresis. The separated proteins from the gel are transferred onto a solid medium

52
Q

What is the advantage of immunohistochemistry

A

The advantage of immunohistochemistry lies in the fact that it is capable of showing exactly where a certain protein is being expressed within a tissue sample

53
Q

What is the first stage of western blotting

A

1 - SDS page electrophoresis is used to separate proteins in the extract ( separated according to size)

54
Q

What is the second stage of western blotting

A

2- the proteins are then transferred to a membrane where they are stained with antibodies. The antibodies bind where the target protein is present

55
Q

What is the third stage of western blotting

A

3 - the membrane is probed with an antibody specific for the protein of interest. It binds where the protein of interest is present

56
Q

What is the fourth stage of western blotting

A

4- stained blot is transferred and fixed to autoradiograph visualise antigen binds that have been stained

57
Q

What is bright field microscopy used for

A

Bright-field microscopy is commonly used to observe whole organisms, parts of organisms, thin sections of dissected tissue or individual cells

58
Q

What is the features of fluorescence microscopy

A

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

59
Q

What is cell structure

A

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

60
Q

What do aseptic techniques eliminate

A

Aseptic technique eliminates unwanted microbial contaminants when culturing micro- organisms or cells

61
Q

What do aseptic techniques involve

A

Aseptic technique involves the sterilisation of equipment and culture media by heat or chemical means and subsequent exclusion of microbial contaminants.

62
Q

How can a microbial culture be started

A

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

63
Q

What type of culture media exists

A

Many culture media exist that promote the growth of specific types of cells and microbes.

64
Q

How are animal cells grown

A

Animal cells are grown in medium containing growth factors from serum

65
Q

What are growth factors in animal cells

A

Growth factors are proteins that promote cell growth and proliferation.

66
Q

What are growth factors essential for

A

Growth factors are essential for the culture of most animal cells.

67
Q

What is the difference between primary cell lines and tumour cell lines

A

In culture, primary cell lines can divide a limited number of times, whereas tumour cells lines can perform unlimited divisions

68
Q

What is the difference between primary cell lines and tumour cell lines

A

In culture, primary cell lines can divide a limited number of times, whereas tumour cells lines can perform unlimited divisions

69
Q

What is the benefit of plaiting out a liquid microbial culture

A

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

70
Q

What is serial dilution

A

Serial dilution is often needed to achieve a suitable colony count

71
Q

What is a haemocytometer used for

A

A hameocytometer may be used to estimate cell numbers in a liquid culture

72
Q

What are the steps for cell counting technique question

A
  1. Count the number of cells in the central square
  2. Work out the volume of each square (lxbxh)
  3. Multiply up to find the number of cells which there would be in 1cm3
73
Q

Why is vital staining required

A

Vital staining is required to identify and count viable cells (only stains dead or living)

74
Q

What is a primary cell line

A

A primary cell line refers to cells that have been isolated and then used immediately. However most animal cells can only perform a finite number of divisions before the cell line can no longer be maintained

75
Q

Tumour cell lines

A

Tumour cell lines can preform an unlimited number of divisions and so the sub culture can be maintained indefinitely