biology - unit 1.1 Flashcards
(59 cards)
What can present a hazard?
Substances, organisms, and equipment in a laboratory.
What do hazards in the lab include?
Toxic or corrosive chemicals, heat or flammable substances, pathogenic organisms, and mechanical equipment.
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 technique.
What do dilutions in a linear dilution series differ by?
An equal interval, for example 0·1, 0·2, 0·3 and so on.
What do dilutions in a log dilution series differ by?
A constant proportion, for example 10-1, 10-2, 10-3 and so on.
What allows the concentration of an unknown to be determined from the standard curve?
Plotting measured values for known concentrations to produce a line or curve.
What do buffers allow?
The pH of a reaction mixture to be kept constant, as the addition of acid or alkali has very small effect on the pH of a buffer.
On a colorimeter, what is the use of absorbance?
Used to determine concentration of a coloured solution using suitable wavelength filters.
On a colorimeter, what is the use of percentage transmission?
Used to determine turbidity, such as cells in suspension.
What is used as a baseline in calibration?
Appropriate blank.
What is a centrifuge used for?
To separate substances of differing density. More dense components settle in the pellet; less dense components remain in the supernatant.
What can paper and thin layer chromatography be used for?
Separating different substances such as amino acids and sugars.
What does the speed that each solute travels along the chromatogram depend on?
Its differing solubility in the solvent used.
What is created for affinity chromatography?
A solid matrix or gel column with specific molecules bound to the matrix or gel.
What becomes attached to these 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.
What does gel electrophoresis do?
It helps separate proteins and nucleic acids.
What do charged macromolecules move through?
An electric field applied to a gel matrix.
What do native gels do?
They separate proteins by their shape, size and charge.
What do native gels do so that separation is by shape, size and charge?
They do not denature the molecule.
What does SDS-PAGE do?
It separates proteins by size alone.
What does SDS-PAGE give?
All the molecules an equally negative charge and denatures them, separating proteins by size alone.
How can proteins be separated from a mixture?
Using their isoelectric points (IEPs).
