Candidate surname Other names
Centre Number Candidate Number
Pearson Edexcel International Advanced Level
Wednesday 17 January 2024
Morning (Time: 1 hour 45 minutes) Paper
reference WBI15/01
Biology
International Advanced Level
UNIT 5: Respiration, Internal Environment,
Coordination and Gene Technology
You must have: Total Marks
Scientific article (enclosed), scientific calculator, ruler, HB pencil
Instructions
•• Use black ink or ball‑point pen.
Fill in the boxes at the top of this page with your name,
centre number and candidate number.
•• Answer all questions.
Answer the questions in the spaces provided
– there may be more space than you need.
Information
•• The total mark for this paper is 90.
The marks for each question are shown in brackets
– use this as a guide as to how much time to spend on each question.
• structure
In questions labelled with an asterisk (*) marks will be awarded for your ability to
your answer logically, showing how the points that you make are related
or follow on from each other where appropriate.
Advice
•• Read each question carefully before you start to answer it.
Try to answer every question.
• Check your answers if you have time at the end.
Turn over
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, Answer ALL questions.
Write your answers in the spaces provided.
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Some questions must be answered with a cross in a box . If you change your mind about an
answer, put a line through the box and then mark your new answer with a cross .
1 Aerobic respiration is made up of several stages.
(a) Which is the correct order of the stages of respiration required for the complete
oxidation of glucose?
(1)
A glycolysis Krebs cycle link reaction
B glycolysis link reaction Krebs cycle
C link reaction Krebs cycle glycolysis
D Krebs cycle glycolysis link reaction
(b) Write a balanced equation for the complete oxidation of glucose in
aerobic respiration.
(2)
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(c) The equation shows the aerobic respiration of a lipid.
2 C18H34O2 + 51 O2 → 36 CO2 + 34 H2O
(i) Which is the respiratory quotient when this lipid is used in aerobic respiration?
(1)
A 0.67
B 0.71
C 1.06
D 1.42
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, (ii) The complete oxidation of one molecule of this lipid produces 122 molecules
of ATP.
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One molecule of this lipid contains 12 244 kJ of energy.
One molecule of ATP yields 30.51 kJ of the energy.
Calculate the percentage of energy in this lipid molecule that can be
converted to energy in ATP.
Give your answer to three significant figures.
(2)
Answer ............................... ................ . . . . . . . . . . . . . . . %
(Total for Question 1 = 6 marks)
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, 2 Impulses are transmitted along nerves as a series of action potentials.
An action potential can be split into four main stages:
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• depolarisation
• repolarisation
• hyperpolarisation
• resting state.
(a) (i) Which row shows the events that happen during depolarisation of a neurone?
(1)
Sodium channels Membrane potential
A closed decreasing
B closed increasing
C open decreasing
D open increasing
(ii) Explain what happens during repolarisation in a neurone.
(3)
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