Students want to test whether doing mental arithmetic changes ruler-drop reaction time. They will use a safe classroom investigation with volunteers. You may compare drop distances directly: longer distances indicate slower reactions.
Plan the investigation so that the results can support a valid comparison.
[6 marks]
4 marksHigher
Spec and skills
Original practice question
Answer and supported method checks
Equal masses of fat are mixed with equal lipase concentrations at 37 °C. A has large droplets at pH 3; B has large droplets at pH 8; C has small droplets at pH 8. This lipase works best near pH 8.
.1
Explain why B should digest fat faster than A.
[2 marks]
.2
Explain why C should be faster than B and relate this to bile.
[2 marks]
4 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
Plant tissue gains 4% mass at 0.20 mol/dm³ sugar and loses 4% at 0.40 mol/dm³. Assume a linear relationship between these points.
.1
Estimate the concentration giving zero net mass change.
[2 marks]
.2
Explain what zero net change means and how to improve the estimate.
[2 marks]
4 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
A chart shows an XX egg-producing parent and an XY sperm-producing parent. A student says that the egg determines whether the child is XX or XY.
.1
Explain why the student’s statement does not follow the chromosome model.
[2 marks]
.2
Explain why an earlier XY child does not make an XX child more likely next time.
[2 marks]
4 marksHigher
Spec and skills
Original practice question
Answer and supported method checks
A clinic diagnoses gonorrhoea in a patient with pain on urination. An initial antibiotic fails; tests identify a resistant bacterial strain.
.1
Explain why an antibiotic can be appropriate for gonorrhoea but this antibiotic failed.
[2 marks]
.2
Explain how a barrier method reduces transmission and why pain relief alone does not prevent spread.
