Biology experiments and data questions

Learning outcomes that say investigate are practical work, and the written paper can ask about them. The skills are the same each time: variables, a fair test, processing results and a justified conclusion.

Variables	Independent, dependent and controlled
Results	Means, rates and percentage changes
Quality	Repeatability, reproducibility, accuracy and error
Our practice	An experiment and data question in every section

Name the variables first

Say what was changed, what was measured and what was kept the same, then say how it was kept the same. A control lets you see the effect of the variable you changed.

Use the numbers

When a question gives data, quote it: the value, the trend and any anomaly. Calculate a mean or a rate where it helps, with units.

Conclude only what the data shows

A conclusion answers the question the experiment asked and stays within the range tested. Suggest an improvement that would make the results more repeatable or more valid.

Try 2 questions

Question 1 · Both levels

Rate of reaction at five substrate concentrations.
Substrate concentration / %	Rate / cm³ of oxygen per minute
0.5	6
1	11
2	18
4	22
8	22

The table shows the rate of an enzyme reaction at five substrate concentrations, with the same amount of enzyme each time. Why does the rate stop rising above 4.0%?

Question 2 · Both levels

Which of these is a disaccharide?

Next step

Take the free test Start the enzymes and energy lesson

Questions people ask

Are there still mandatory experiments?

The new specification sets learning outcomes, some of which say investigate. Your teacher plans the practical work that meets them.

Do I need to learn exact methods?

Know why each step is done. Questions often change the details, so understanding beats memorising.