Unit 1 - section 1 Flashcards
Name 2 things that can be intrinsically harmful when working in a lab.
Chemicals
Organisms
Who or what is at risk in a lab?
People
Other organisms
Environment
Name the control measures
Elimination Substitution Isolation Education Personal protective equipment
Describe elimination
The hazardous chemical/ organism is replaced with a less harmful equivalent or the step is removed from the protocol
Describe substitution
If the hazard is very particular to a chemical/ organism involved it may be possible to use alternatives which do not produce the same level of risk
Describe isolation
The procedure would be carried out in a contained environment
Describe education (control measure)
People would be trained to follow standard methods of practice that reduce the risk
Describe personal protective equipment
Can include wearing a lab coat, dust mask, gloves etc
What is the purpose of risk assessments?
To enable any hazards to be identified and ensure appropriate safety is in place to minimise the risk. Ensures working conditions are safe.
What are burettes used for?
For titration. Can make accurate measurements of small volumes
What are pipettes used for?
Less accurate than other methods. Bulb is depressed before insertion into the liquid and then gently (almost fully) released
What are syringes used for?
Very accurate method of measurement
What are autopipettes used for?
Allow w small volumes of liquid to measures very accurately. A disposable tip is used to prevent contamination
What are measuring cylinders used for?
Measuring volumes between 5 and 2000cm3. Scale is read from the bottom of the meniscus
Define the term dilution
To make a solution less concentrated by adding another solution or water
Formula for dilution calculations
V1C1=V2C2
Describe log dilution
Performed using a variety of chemicals or microorganisms.
Involves dilution by 1/10 each time
Useful when culturing microbes
Describe linear dilution
Involves even quantity separations
Useful for standard curves
What is a standard curve and what is it used for?
A graph of known concentrations that allows you to determine unknown concentrations
How can pH be controlled in an experiment?
By adding a buffer solution
2 ways pH can be tested
PH meter
Universal indicator and a colour chart
Describe the process of centrifugation
Used to separate substances by their density.
Define the terms pellet and supernatant
Pellet- solid that’s forms at the bottom of the vessel as the machine spins
Supernatant- the remaining liquid
How are the pellet and supernatant formed during centrifugation
As the material is rotated in the centrifuge tube the resulting g-force causes the constituents to separate
Name the 3 types of chromatography
Paper
Thin-layer
Affinity
Describe paper chromatography
Amino acids with different solubilities travel different distances up the paper support
Describe thin-layer chromatography
Amino acids with differing solubilities travel different distances up the solid support eg glass/ plastic coated in gel
Describe affinity chromatography
Separating biochemical mixtures based on a highly specific interaction. The molecules that are to be separated will bind to the equipment, which will be designed to only attract that substance.
Example interactions- antigen and antibody, enzyme and substrate, receptor and ligand
2 types of molecules that can be separated using chromatography
Amino acids
Proteins