2026/2027 AQA GCSE COMBINED SCIENCE: SYNERGY 8465/3H Paper 3 Question Paper + Mark Scheme + Inserts

Enzymes are large molecules and biological catalysts.
0 1 . 1 What type of molecule is an enzyme?
[1 mark]
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0 1 . 2 A catalyst changes the rate of a chemical reaction.
What happens to the mass of a catalyst during a chemical reaction?
[1 mark]
Tick () one box.
The mass of the catalyst decreases.
The mass of the catalyst stays the same.
The mass of the catalyst increases.
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Do not write
outside the
box
Turn over U
Figure 1 shows a model of enzyme action.
Figure 1
Enzyme
X
Y
0 1 . 3 Name X and Y in Figure 1.
[2 marks]
X _________________________________________________________________________________
Y _________________________________________________________________________________
0 1 . 4 Name the model shown in Figure 1.
[1 mark]
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Question 1 continues on the next page
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(04) G/Jun24/8465/3H
Do not write
outside the
box Amylase is an enzyme that breaks down starch.
A student investigated how changing the pH affected the activity of amylase.
This is the method used.
1. Heat a test tube containing 2 cm3 of amylase solution at pH 5.0 in a water bath
at 35 °C.
2. Heat a test tube containing 2 cm3 of starch solution in the same water bath.
3. Transfer the amylase solution into the test tube of starch solution and mix.
4. After 30 seconds remove a drop of the amylase–starch mixture and
test the drop for starch.
5. Repeat step 4 until no starch is detected.
6. Record the total time taken for no starch to be detected.
7. Repeat steps 1 to 6 using amylase solution at different pH values.
0 1 . 5 Explain why the solutions are all placed in the same water bath.