Cells and Proteins - Laboratory Techniques Flashcards
What can present a hazard in a lab?
Substances, organisms and equipment
What do hazards in a lab include?
Toxic or corrosive chemicals, heat or flammable substances, pathogenic organisms, and mechanical
equipment
Define risk?
The likelihood of harm arising from exposure to a hazard
What does a risk assessment involve?
Identifying control measures to minimise the risk
What are examples of control measures?
Using appropriate handling techniques, protective clothing and equipment, and aseptic technique
Describe linear dilution?
Dilutions in a linear dilution series differ by an equal interval, for example 0·1, 0·2, 0·3 and so on
Describe log dilution?
Dilutions in a log dilution series differ by a constant proportion, for example 10-1, 10-2, 10-3 and so on
How can the concentration of an unknown be determined from the standard curve?
By plotting measured values for known concentrations to produce a line or curve
What are buffers used for?
To control pH
How do buffers control pH?
Addition of acid or alkali has very small effects on the pH of a buffer, allowing the pH of a reaction mixture to be kept constant
How are colorimeters used to quantify concentration?
Absorbance to determine concentration of a coloured solution using suitable wavelength filters
How are colorimeters used to quantify turbidity?
Use of percentage transmission to determine turbidity, such as cells in suspension
What is the separation technique centrifuge used for?
To separate substances of different density
How does centrifuge work?
More dense components settle in the pellet; less dense components remain in the supernatant
What separation technique is used for separating different substances such as amino acids and sugars?
Paper and thin layer chromatography
How does paper and thin layer chromatography work?
The speed that each solute travels along the chromatogram depends on its differing solubility in the solvent used
How does affinity chromatography work?
A solid matrix or gel column is created with specific molecules bound to the matrix or gel. Soluble, target proteins in a mixture, with a high affinity for these molecules, become attached to them as the mixture passes down the column. Other non-target molecules with a weaker affinity are washed out
How does gel electrophoresis work?
It separates proteins and nucleic acids.
Charged macromolecules move through an electric field applied to a gel matrix
How do native gels work?
They do not denature the molecule (protein) so that separation is by shape, size and charge
How does SDS-PAGE work?
It gives all the molecules an equally negative charge and denatures them, separating proteins by size alone
