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A-Level OCR 2025 Biology B (Advancing
poH422/01 Fundamentals of biology Biology) Paper 1
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Section A
You should spend a maximum of 40 minutes on this section.
Write your answer for each question in the box provided.
1 Which type of blood cell is shown in the annotated drawing?
Non-granulated cytoplasm
Kidney-bean shaped nucleus
A Erythrocyte
B Lymphocyte
C Monocyte
D Neutrophil
Your answer [1]
2 Which technique uses fluorescent markers to tag cells so they can be counted and identified
when passed through a laser beam?
A Differential staining
B Flow cytometry
C Gel electrophoresis
D Haemocytometry
Your answer [1]
© OCR 2025
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3 Which statement about ATP is not correct?
A It can be hydrolysed to form AMP.
B It contains the pentose sugar, ribose.
C It contains the pyrimidine nitrogenous base, adenine.
D It is a phosphorylated nucleotide.
Your answer [1]
4 The percentage base composition of DNA from a species of octopus is shown in the table.
Base Adenine X Y Z
% base composition 33.2 17.6 17.5 31.7
of DNA
Which option correctly identifies bases X, Y and Z?
A Base X is cytosine, Y is guanine and Z is thymine.
B Base X is cytosine, Y is guanine and Z is uracil.
C Base X is thymine, Y is cytosine and Z is guanine.
D Base X is uracil, Y is cytosine and Z is guanine.
Your answer [1]
5 A student calculated cardiac output (CO) using the equation:
CO = heart rate × stroke volume.
What unit of measurement is appropriate for cardiac output?
A bpm cm–3
B cm3 bpm
C dm–3 min–1
D dm3 min–1
Your answer [1]
© OCR 2025 Turn over
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6 Which of the following statements about the advantages of a closed circulatory system is/are
correct?
1 Deoxygenated and oxygenated blood are separated.
2 Higher blood pressure is maintained in both pulmonary and systemic circuits.
3 Low blood volumes can maintain movement in the circulatory system.
A 1, 2 and 3 are correct
B Only 1 and 2 are correct
C Only 2 and 3 are correct
D Only 1 is correct
Your answer [1]
7 Alveoli are structures found in the mammalian gaseous exchange system.
Which cells would be present in the walls of alveoli?
A Ciliated epithelial cells
B Goblet cells
C Muscle cells
D Squamous epithelial cells
Your answer [1]
8 The surface area provided by a single alveolus is approximately 300 000 μm2.
A person was estimated to have 250 million alveoli in each lung.
What is the estimated gas exchange surface area in m2 for this person?
A 7.5 × 101
B 1.5 × 102
C 7.5 × 107
D 1.5 × 108
Your answer [1]
© OCR 2025