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• What can present a hazard in a laboratory ?

  Substances, organisms and equipment
• Hazards in the lab include

  Toxic or corrosive chemicals, heat or flammable substances, pathogenic organisms and mechanical equipment
• The use of hazards may involve risks to


  people, other organisms, or the environment
• How are hazards, risks controlled in the lab ?

  Risk assessment
• What is risk ?

  the likelihood of harm arising from exposure to a hazard
• What does risk assessment involve ?

  identifying control measures to minimise the risk
• What do control measures include ?

  Using appropriate handling techniques, protective clothing and equipment and aseptic techniques
• Dilutions in __________ dilution series differ by a equal interval e.g. 0.1, 0.2, 0.3

  linear
• Dilutions in __________ dilution series differ by a constant proportion eg. 10-1, 10-2, 10-3

  log
• Why is a standard curve produced ?

  It is used to 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 a standard curve.
• What effect does the addition of acids and alkalis have on the pH on a buffer ?

  has very small effects and allows the pH of a reaction mixture to be kept constant
• How can pH be measured ?

  a meter and indicators
• What do colourimeters measure ?

  concentration and turbidity
• How and why do you calibrate a colourimeter ?

  Using an appropriate blank as a baseline
• Absorbance determines

  concentration of a coloured solution using suitable wavelength filters
• Percentage transmission determines

  turbidity
• Using centrifugation separate substances with

  differing density
• More dense components

  settle in the pellet

  
• Less dense components

  remain in the supernatant

  
• What can be used to separating different substances (amino acids and sugars) ?

  Paper and this layer chromatography
• The speed that each solute travels along the chromatogram depends on its

  differing solubility in the solvent used
• Affinity chromatography is used in ...

  separating proteins
• A solid matrix or gel is created with ___________ bound to the matrix or gel

  specific molecules
• Soluble, target proteins in a mixture, with high affinity for these molecules do what ? (affinity chromatography)


  Become attached to them as the mixture passes down the column
• Non target molecules have ... (affinity chromatography)


  a weaker affinity and are washed out
• Gel electrophoresis is used

  to separate proteins and nucleic acids
• What happens in gel electrophoresis ?

  charged molecules move through an electric field applied to a gel matrix
• Native gels separates proteins by

  shape, size and charge
• SDS Page seperates proteins by

  size alone
• SDS-PAGE gives all the molecules a

  equally negative charge and denatures them, separating proteins by size alone
• IEPs are

  Isoelectric points and proteins can be separated from a mixture using them
• IEP is the pH at which ...

  a soluble protein has no net charge and will precipitate out of solution
• If a solution is buffered to a specific pH, only ...

  proteins that have an IEP of that pH will precipitate
• proteins can also separated using their IEP

  in electrophoresis
• Soluble proteins can be separated by using

  an electric field and a pH gradient
• Why does a protein stops migrating through the gel at its IEP in the pH gradient ?

  It has no net charge
• What are immunoassay techniques used for ?

  To detect and identify specific proteins
• immunoassay techniques are used

  stocks of antibodies with the same specificity, known as monoclonal antibodies
• Imunnoassay techniques use what ?

  stocks of antibodies with the same specificity, which are known as monoclonal antibodies