UNIT 1 - KA1 Flashcards
What is a hazard
A hazard is a source of potential harm
What are hazards in the lab (4)
toxic, or corrosive chemicals
heat or flammable substances
Pathogenic organisms
Mechanical equipment
What is a risk
Risk is the likelihood of harm arising from exposure to a hazard
Risk assessment
Risk assessment involves identifying control measures to minimise the risk
Control measures
Appropriate handling techniques
Protective clothing and equipment
Aseptic technique
What is a ph buffer
A ph buffer is a solution whose pH changes very little when a small amount of acid or base is added to it
How do buffers work
Buffers work by allowing the addition of hydrogen or hydroxide ions without affecting the pH of the solution
Why are buffer solutions used
Buffer solutions are used as a means of keeping ph at a nearly constant value
What is the application of centrifugation
Separation according to density
How does a centrifuge separate substances of differing density
More dense compounds settle in the pallet whereas less dense components remain in the supernatant
What are the names given to the solid and liquid in a centrifuge tube
The solid found at the base of the tube is called the pellet and the liquid the supernatant
What are linear dilutions used for
Used if you need a sample over a reasonably small range
How do dilutions in a linear dilution series differ
Dilutions in a linear dilution series differ by an equal interval for example 0.1, 0.2 ,0.3 and so on.
What are serial (log dilutions) used for
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
How do dilutions in a log dilution series differ
Dilutions in a log dilution series differ by a constant proportion, eg 10^-1 , 10^-2 , 10^-3 and so on
How does the production of a standard curve determine an unknown
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
What can paper and thin layer chromatography be used for
Paper and thin layer chromatography can be used for separating different substances such as amino acids and sugars
What does the speed at which the solute travels through the chromatogram depend on
The speed that each solute travels along the chromatogram depends on its differing solubility in the solvent used
How is a solid matrix or gel column created
A solid matrix or gel column is created with specific molecules bound to the matrix or gel
What happens to soluble target proteins in affinity chromatography
Soluble target proteins in a mixture with high affinity for these molecules become attached to them as the mixture passes down the column
What happens to non target molecules in affinity chromatography
Other non - target molecules with a weaker affinity are washed out
What is the process of electrophoresis
Electrophoresis is the process of moving charged molecules in solution by applying an electric field across the mixture
What three factors determine the speed at which molecules move in protein electrophoresis
The molecules move with a speed dependant on their charge, shape size and so they can be separated from other molecules using this technique
What is the gel in gel electrophoresis made of
The gel is made of agarose
How is the tank set up in gel electrophoresis
The tank is set up with a positive and negative terminal and an electric current is applied
Where do the fragments move towards in gel electrophoresis
The fragments move towards the electrode which is of the opposite charge to the fragments
Where do smaller and larger fragments move to
Smaller fragments move more Quickly (do not get tangled on the agarose protein strands) than the larger fragments.
How do native gels separate proteins
Native gels separate proteins by their shape, size and charge
How do native gels separate by shape size and charge
Native gels do not denature the molecule so that separation is by shape, size and charge.
How does SDS page separate proteins
SDS page gives all the molecules an equally negative charge and denatures them separating proteins by size alone