This free quiz has 26 multiple choice questions on practical skills, all taken from OCR A Level Biology A exam papers. It marks itself, so you get your score as soon as you finish.
What the quiz covers (OCR A spec Module 1)
Choosing suitable controls and identifying variables when planning an investigation
Appropriate units for rates and measurements
Reading and interpreting graphs, including growth curves, gradients and error bars
Choosing the right statistical test for a question and a data set
Percentages, proportions and estimates from population data
Percentage uncertainty in measurements, and accuracy versus precision
Serial dilutions and working out concentrations
Spotting limitations and judging the validity of an investigation
How to use it
Have a calculator, ruler and scrap paper ready, and work calculations through rather than estimating. For graph and table questions, read the axis labels, units and scales before looking at the options.
Where students lose marks (from OCR examiners' reports and mark schemes)
Each point below is followed by wording that gained marks.
Percentage change from the start: Many students divided the change by the final value instead of the starting value, or used one of the readings itself rather than the difference between them.
✔ Gains credit: Finding the difference first, dividing it by the original (starting) value and multiplying by 100, then rounding to the number of significant figures asked for.
Why percentage change is used: Many students said converting to percentage change makes results more precise, accurate or reliable, or gave only half of the reason.
✔ Gains credit: Both ideas together: the starting masses of the tissue pieces differ, so percentage change allows a fair comparison between pieces.
Radius, not diameter: Many students put the tube's diameter into the formula for the area of a circle instead of halving it, forgot to square the radius, or did not divide by the time, in the right unit, to turn a volume into a rate.
✔ Gains credit: Halving the diameter, squaring the radius, multiplying by pi and the distance moved, then dividing by the time in the units asked for, for example converting minutes to seconds, to give a rate such as mm³ s⁻¹.
Gradients that miss the origin: Many students found a rate from a straight-line graph by dividing one y value by its x value, forgetting that the line did not start at zero, which overestimated the gradient.
✔ Gains credit: Dividing the change in y by the change in x between two points on the line, and reading the intercept at time zero from the graph rather than assuming it is zero.
Correlation, not cause: Many students turned a relationship shown on a graph into a causal claim, or added reasons for the trend that could not be validly concluded from the data.
✔ Gains credit: Describing the relationship itself, for example 'there is a positive correlation' or 'as body mass increases, lifespan increases', without claiming that one variable causes the change in the other.
Units in headings, not cells: Many students wrote units next to every value in the body of the table, used inconsistent decimal places, gave headings that did not say what was measured, or did not put the independent variable on the left.
✔ Gains credit: A ruled table with the independent variable in the left-hand column, informative headings that carry the units, no units in the body, and values recorded to a consistent number of decimal places.
Naming precise apparatus: Many students named equipment too vaguely or wrongly, such as an unqualified 'pipette', a water bath on its own, or a calorimeter when a colorimeter was needed.
✔ Gains credit: Specific apparatus matched to its purpose, such as a graduated pipette, syringe or burette for measuring volumes, a thermostat or thermometer to control and monitor temperature, a colorimeter for pigment concentration and a biosensor for blood glucose.
Keep practising
Go on to the Enzymes quiz, the Biodiversity quiz or the Food Tests quiz, or browse all our OCR A Level Biology quizzes. Our OCR A masterclasses (Year 12 on Wednesdays at 5.15pm, Year 13 on Tuesdays at 6.30pm) work through real exam questions on one topic each week.