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 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]
5 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
A genetically engineered crop produces a protein harmful to one insect pest. Small field trials report less insect damage, but did not measure other insect populations.
.1
Explain how genetic engineering can produce the new crop characteristic.
[2 marks]
.2
Evaluate whether the trial establishes that large-scale use has no ecological disadvantages.
[3 marks]
5 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
A student says: "DNA is copied after mitosis because daughter cells only need half the genetic information at first."
.1
Explain why this account is incorrect.
[3 marks]
.2
Explain why mitosis is useful in healing a skin wound.
[2 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.
