GCSE Required Practical “Cheat Sheet”
While we have done loads of practicals over the GCSE course some are
specifically mentioned in the syllabus and thus you are supposed to know more
about them: in particular you could be asked questions on them or about the
techniques within them.
I have outlined these 10 key practicals below. Please note that they might well
ask you to apply the techniques and ideas to a new situation, so just knowing the
practicals inside out is not enough. I have given you snippets of information
about each practical to help you remember them. A lot of the information is
directly from AQA and so is exactly what might come up in the exam. If you are
really not sure about these practicals then there is a separate document on the
Gateway (and in your email) that gives more detail about what happened in
each;.
If you get a question in the exams which is explicitly about an experiment it
would be really helpful to think about which of these practicals it relates to
Other Practical Advice
It is highly likely that you will be asked to PLAN a practical in at least one of the
papers, in which case you need to think about
“CORMS”
C Compar What are you going to change? How will you change it?
e
O Organis What is the organism you are going to use? What about it will
m you need to control (i.e. keep the same)?
R Repeats ALWAYS mention doing repeats!
M Measur What are you going to measure? How (exactly) are you going
e to do this?
S Same What factors do you need to control (i.e. keep the same)?
Sometimes you might also be asked to comment on a method.
Here you need to think about question like:
Have variables been controlled?
Have repeats been done?
Does the experiment actually answer the question you are interested in?
What in the experiment is difficult to do and thus a (potential) source of
error?
Do you need more data at specific points (e.g. to work out the optimum
temperature for an enzyme)?
,Here are the 10 key practicals
1. Microscopy (Paper 1)
Use a light microscope to observe, draw and label biological specimens.
Students should make clear, labelled diagrams of the cells they observe and
include the magnification. (i.e. you need to be able to do magnification
calculations)
2. Microbiology (Paper 1)
Investigate the effect of antiseptics or antibiotics on bacterial growth using agar
plates and measuring zones of inhibition.
Students should be aware of the need for good aseptic techniques and what
these are, for example:
Technique Additional information
Flaming the neck of This must be done whilst still holding the pipette and the
the culture lid of the culture bottle in your other hand (neither should
be placed down on the bench at any point). The bottle
must not be held still in the flame as the glass will crack –
it should be rotated as it is very briefly passed through
the flame.
Lifting the lid of the The lid should only be opened at the side facing the
agar plate at an Bunsen burner to avoid contamination.
angle
Placing drops of This needs to be done while carefully holding the lid over
culture from the the plate.
pipette onto the
agar.
Spreading the This is best done by holding the glass spreader still up to
bacteria thoroughly the edge of the plate and rotating the plate. The lid of
around the agar the plate must be held over it at the same time to avoid
plate right to the contamination.
edges
Placing the filter Students should hold the first disc with the forceps. They
paper discs onto should lift the lid of the agar plate at an angle (as before)
the agar plate in and place the disc flat onto the central dot in the first
the right positions. third of the plate. The lid of the agar plate should be
replaced whilst the next disc is collected. This is repeated
so that all three discs are in position.
Clear zones are not always perfectly circular so students should measure the
diameter twice (at 90° to each other) and calculate a mean diameter and area
for each clear zone.
, 3. Osmosis (Paper 1)
Investigate the effect of a range of concentrations of salt or sugar solutions on
the mass of plant tissue.
Students should be able to:
calculate percentage changes in mass
plot positive and negative values on a graph
obtain an estimate of the concentration of cytoplasm from looking at the
x-intercept of their graph.
While we have done loads of practicals over the GCSE course some are
specifically mentioned in the syllabus and thus you are supposed to know more
about them: in particular you could be asked questions on them or about the
techniques within them.
I have outlined these 10 key practicals below. Please note that they might well
ask you to apply the techniques and ideas to a new situation, so just knowing the
practicals inside out is not enough. I have given you snippets of information
about each practical to help you remember them. A lot of the information is
directly from AQA and so is exactly what might come up in the exam. If you are
really not sure about these practicals then there is a separate document on the
Gateway (and in your email) that gives more detail about what happened in
each;.
If you get a question in the exams which is explicitly about an experiment it
would be really helpful to think about which of these practicals it relates to
Other Practical Advice
It is highly likely that you will be asked to PLAN a practical in at least one of the
papers, in which case you need to think about
“CORMS”
C Compar What are you going to change? How will you change it?
e
O Organis What is the organism you are going to use? What about it will
m you need to control (i.e. keep the same)?
R Repeats ALWAYS mention doing repeats!
M Measur What are you going to measure? How (exactly) are you going
e to do this?
S Same What factors do you need to control (i.e. keep the same)?
Sometimes you might also be asked to comment on a method.
Here you need to think about question like:
Have variables been controlled?
Have repeats been done?
Does the experiment actually answer the question you are interested in?
What in the experiment is difficult to do and thus a (potential) source of
error?
Do you need more data at specific points (e.g. to work out the optimum
temperature for an enzyme)?
,Here are the 10 key practicals
1. Microscopy (Paper 1)
Use a light microscope to observe, draw and label biological specimens.
Students should make clear, labelled diagrams of the cells they observe and
include the magnification. (i.e. you need to be able to do magnification
calculations)
2. Microbiology (Paper 1)
Investigate the effect of antiseptics or antibiotics on bacterial growth using agar
plates and measuring zones of inhibition.
Students should be aware of the need for good aseptic techniques and what
these are, for example:
Technique Additional information
Flaming the neck of This must be done whilst still holding the pipette and the
the culture lid of the culture bottle in your other hand (neither should
be placed down on the bench at any point). The bottle
must not be held still in the flame as the glass will crack –
it should be rotated as it is very briefly passed through
the flame.
Lifting the lid of the The lid should only be opened at the side facing the
agar plate at an Bunsen burner to avoid contamination.
angle
Placing drops of This needs to be done while carefully holding the lid over
culture from the the plate.
pipette onto the
agar.
Spreading the This is best done by holding the glass spreader still up to
bacteria thoroughly the edge of the plate and rotating the plate. The lid of
around the agar the plate must be held over it at the same time to avoid
plate right to the contamination.
edges
Placing the filter Students should hold the first disc with the forceps. They
paper discs onto should lift the lid of the agar plate at an angle (as before)
the agar plate in and place the disc flat onto the central dot in the first
the right positions. third of the plate. The lid of the agar plate should be
replaced whilst the next disc is collected. This is repeated
so that all three discs are in position.
Clear zones are not always perfectly circular so students should measure the
diameter twice (at 90° to each other) and calculate a mean diameter and area
for each clear zone.
, 3. Osmosis (Paper 1)
Investigate the effect of a range of concentrations of salt or sugar solutions on
the mass of plant tissue.
Students should be able to:
calculate percentage changes in mass
plot positive and negative values on a graph
obtain an estimate of the concentration of cytoplasm from looking at the
x-intercept of their graph.
