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]
5 marksHigher
Spec and skills
Original practice question
Answer and supported method checks
Four plants all have genotype RR at one tested gene, but their final heights are 14, 19, 24 and 27 cm. The plants grew with different supplies of water. A student claims that these results show height cannot be inherited.
.1
Explain why the student’s conclusion is not justified.
[3 marks]
.2
Suggest how to test the effect of water while reducing genetic differences between plants.
[2 marks]
4 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
The diagram shows a student's drawing of a plant cell.
.1
The student has not drawn a cell membrane. Explain why a plant cell needs both a cell wall and a cell membrane.
[2 marks]
.2
The label 'aerobic respiration' points to the wrong structure. Name the structure it should point to, and explain why the cell needs to respire.
[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 contraceptive comparison gives typical-use pregnancies per 100 users in one year: method A, a daily hormonal pill, 8; method B, an implant, 1. Neither method protects against sexually transmitted infections.
.1
Calculate the difference in expected pregnancies between 500 users of A and 500 users of B for one year.
[2 marks]
.2
A person often forgets daily medication and also wants infection protection. Evaluate these methods for that person.
