5 marksFoundation and HigherRequired practical 044.2.2.1 The human digestive system
AQA Trilogy 8464
Spec and skills
Paper scope: B1
Spec 4.2.2.1
Original practice question
Answer and supported method checks
A student investigated the effect of pH on the time taken for amylase to break down starch.
She mixed amylase, starch and a buffer solution in a water bath at 35 °C. Every 30 seconds she put a drop of the mixture onto iodine solution on a spotting tile. She recorded the time when the iodine no longer turned blue-black.
Time for starch to be broken down: pH 5, 150 s; pH 6, 90 s; pH 7, 60 s; pH 8, 120 s; pH 9, 240 s.
pH
Time for starch to be broken down (s)
5
150
6
90
7
60
8
120
9
240
.1
The rate of reaction can be found with:
rate =time1000
Calculate the rate of reaction at pH 7.
[1 mark]
.2
Explain why the starch took much longer to break down at pH 9.
[2 marks]
.3
Suggest how the student could find the optimum pH of amylase more precisely.
[1 mark]
.4
Sampling every 30 seconds limits the accuracy of the times.
Explain why.
[1 mark]
4 marksFoundation and Higher4.2.2.6 The effect of lifestyle on some non-communicable diseases4.2.2.7 Cancer
AQA Trilogy 8464
Spec and skills
Paper scope: B1
Spec 4.2.2.6
Spec 4.2.2.7
Original practice question
Answer and supported method checks
Scientists studied the risk of lung cancer in adults who smoked different numbers of cigarettes each day. The graph shows how many times greater the risk was than for non-smokers.
051015202530510152025Cigarettes smoked per dayRisk compared with non-smokers1481522
.1
Describe the pattern shown in the graph.
[1 mark]
.2
Calculate how many times as great the risk is for a person smoking 20 cigarettes a day as for a person smoking 5 a day.
[1 mark]
.3
A correlation does not always mean that one factor causes another.
Explain what other evidence scientists needed before concluding that smoking causes lung cancer.
[2 marks]
4 marksFoundation4.1.1.2 Animal and plant cells4.1.1.1 Eukaryotes and prokaryotes
AQA Trilogy 8464
Spec and skills
Paper scope: B1
Spec 4.1.1.2
Spec 4.1.1.1
Original practice question
Answer and supported method checks
Animal cells, plant cells and bacterial cells contain different structures.
.1
What is the function of mitochondria?
[1 mark]
.2
Name the structure in a plant cell that absorbs light for photosynthesis.
[1 mark]
.3
Which two structures are found in a bacterial cell? Tick two boxes.
[2 marks]
4 marksFoundation and Higher4.2.1 Principles of organisation
AQA Trilogy 8464
Spec and skills
Paper scope: B1
Spec 4.2.1
Original practice question
Answer and supported method checks
The stomach contains muscular tissue, glandular tissue and epithelial tissue.
.1
Define the term tissue.
[1 mark]
.2
Explain why the stomach is described as an organ.
[2 marks]
.3
Muscular tissue in the stomach wall contracts. What does this do?
[1 mark]
6 marksFoundation and Higher4.2.3.2 Plant organ system
AQA Trilogy 8464
Spec and skills
Paper scope: B1
Spec 4.2.3.2
Original practice question
Answer and supported method checks
A student used a potometer to measure the rate of water uptake by a leafy shoot. An air bubble moved along a scale as the shoot took up water.
In still air the bubble moved 45 mm in 5 minutes. With a fan blowing on the shoot, the bubble moved 72 mm in 5 minutes.
.1
Calculate the rate of water uptake in still air, in mm per minute.
[1 mark]
.2
Calculate the percentage increase in the rate when the fan was on.
[2 marks]
.3
Explain why the rate of water uptake increased when the fan was on.
[2 marks]
.4
Give one variable the student should keep the same when comparing still air with moving air.
