1.1 Lab Techniques for Biologists (Up to Separation Techniques) Flashcards
What is the definition of a hazard
A hazard can be considered as anything that poses a potential threat to an individual or the environment
What is the definition of a risk?
Risk is the likelihood of harm arising from a hazard
What is risk assessment?
Risk assessment involves identifying control
measures to minimise the risk
What are some control measures?
Control measures include:
- Personal Protective Equipment (PPE): Lab coat, goggles, gloves, long trousers, close-toed shoes
- Using appropriate handling techniques
- Aseptic technique
What are the two types of dilution series?
Serial/logarithmic dilution and linear dilution
How do linear dilution and serial dilution differ?
Dilutions in a linear dilution series differ by an
equal interval, for example 0·1, 0·2, 0·3 and
so on whereas dilutions in a log dilution series differ by a constant proportion, for example 10^(-1), 10^(-2), 10^(-3) and so on.
What are standard curves used to determine?
The concentration of an unknown solution
How is a standard curve produced and how does it allow you to determine the concentration of an unknown?
Plotting measured values for known
concentrations to produce a line or curve
allows the concentration of an unknown to be
determined from the standard curve
What is a buffer solution?
A solution in which the 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
What is a colorimeter used to quantify?
Concentration and turbidity
What could be used as an appropriate blank to calibrate a colorimeter?
Distilled/deionised water
How does a colorimeter measure absorbance?
use of absorbance to determine concentration of a coloured solution using suitable wavelength filters
How does a colorimeter measure turbidity?
use of percentage transmission to determine turbidity, such as cells in suspension
What does a centrifuge do?
separates substances of differing density
How does a solution separate in the centrifuge?
More dense components settle in the pellet; less dense components remain in the supernatant
