Thursday 4 June 2026 – Afternoon
A Level Biology A
H420/01 Biological processes
Time allowed: 2 hours 15 minutes
You can use:
*
• a scientific or graphical calculator
• a ruler (cm/mm)
* H 4 2 0 0 1 *
*
Please write clearly in black ink. Do not write in the barcodes.
Centre number Candidate number
First name(s)
Last name
INSTRUCTIONS
• Use black ink. You can use an HB pencil, but only for graphs and diagrams.
• Write your answer to each question in the space provided. If you need extra space use
the lined page at the end of this booklet. The question numbers must be clearly shown.
• Answer all the questions.
• Where appropriate, your answer should be supported with working. Marks might be
given for using a correct method, even if your answer is wrong.
INFORMATION
• The total mark for this paper is 100.
• The marks for each question are shown in brackets [ ].
• Quality of extended response will be assessed in questions marked with an asterisk (*).
• This document has 28 pages.
ADVICE
• Read each question carefully before you start your answer.
Cambridge OCR 2026 [601/4260/1] Cambridge OCR is an exempt Charity
DC (WW/SW) 359625/6 Turn over
, 2
Section A
You should spend a maximum of 20 minutes on this section.
Write your answer to each question in the box provided.
1 Which statement about differential stains is correct?
A They are only used to stain living specimens.
B They only stain the cell surface membrane.
C They stain all parts of a cell.
D They stain specific cell structures.
Your answer [1]
2 The table compares light and transmission electron microscopes.
Transmission electron
Feature Light microscope
microscope (TEM)
Resolution 200 nm 0.5 nm
Magnification up to 2000 × more than 500 000 ×
Ribosomes are approximately 20 nm in diameter.
Based on the information in the table, which statement is correct?
A Ribosomes can be seen in micrographs taken with a light microscope if the micrograph is
enlarged on a scanner or photocopier.
B Ribosomes can be seen in micrographs taken with a TEM but not a light microscope.
C Ribosomes can be seen in micrographs taken with either a light microscope or a TEM.
D Ribosomes cannot be seen in a micrograph taken with either a light microscope or a TEM.
Your answer [1]
Cambridge OCR 2026
, 3
3 Which statement describes the formation of a DNA polynucleotide?
A Deoxyribonucleotides bond together via purines in condensation reactions.
B Many deoxyribonucleotides join forming a sugar phosphate backbone.
C Many ribonucleotides join forming a sugar phosphate backbone.
D Ribonucleotides bond together via purines in condensation reactions.
Your answer [1]
4 Which process happens during breathing out at rest?
A Elastic fibres in the walls of the alveoli recoil.
B The diaphragm contracts.
C The external intercostal muscles contract.
D The internal intercostal muscles contract.
Your answer [1]
5 Which statement about the mammalian gas exchange system is correct?
A Cartilage supports the walls of the alveoli to prevent collapse during inspiration.
B Goblet cells line the alveoli and secrete mucus to trap dust particles and bacteria.
C Smooth muscle in the walls of bronchioles contracts to control air flow into alveoli.
D Trachea divide to form many small tracheoles that carry air to the alveoli.
Your answer [1]
Cambridge OCR 2026 Turn over
A Level Biology A
H420/01 Biological processes
Time allowed: 2 hours 15 minutes
You can use:
*
• a scientific or graphical calculator
• a ruler (cm/mm)
* H 4 2 0 0 1 *
*
Please write clearly in black ink. Do not write in the barcodes.
Centre number Candidate number
First name(s)
Last name
INSTRUCTIONS
• Use black ink. You can use an HB pencil, but only for graphs and diagrams.
• Write your answer to each question in the space provided. If you need extra space use
the lined page at the end of this booklet. The question numbers must be clearly shown.
• Answer all the questions.
• Where appropriate, your answer should be supported with working. Marks might be
given for using a correct method, even if your answer is wrong.
INFORMATION
• The total mark for this paper is 100.
• The marks for each question are shown in brackets [ ].
• Quality of extended response will be assessed in questions marked with an asterisk (*).
• This document has 28 pages.
ADVICE
• Read each question carefully before you start your answer.
Cambridge OCR 2026 [601/4260/1] Cambridge OCR is an exempt Charity
DC (WW/SW) 359625/6 Turn over
, 2
Section A
You should spend a maximum of 20 minutes on this section.
Write your answer to each question in the box provided.
1 Which statement about differential stains is correct?
A They are only used to stain living specimens.
B They only stain the cell surface membrane.
C They stain all parts of a cell.
D They stain specific cell structures.
Your answer [1]
2 The table compares light and transmission electron microscopes.
Transmission electron
Feature Light microscope
microscope (TEM)
Resolution 200 nm 0.5 nm
Magnification up to 2000 × more than 500 000 ×
Ribosomes are approximately 20 nm in diameter.
Based on the information in the table, which statement is correct?
A Ribosomes can be seen in micrographs taken with a light microscope if the micrograph is
enlarged on a scanner or photocopier.
B Ribosomes can be seen in micrographs taken with a TEM but not a light microscope.
C Ribosomes can be seen in micrographs taken with either a light microscope or a TEM.
D Ribosomes cannot be seen in a micrograph taken with either a light microscope or a TEM.
Your answer [1]
Cambridge OCR 2026
, 3
3 Which statement describes the formation of a DNA polynucleotide?
A Deoxyribonucleotides bond together via purines in condensation reactions.
B Many deoxyribonucleotides join forming a sugar phosphate backbone.
C Many ribonucleotides join forming a sugar phosphate backbone.
D Ribonucleotides bond together via purines in condensation reactions.
Your answer [1]
4 Which process happens during breathing out at rest?
A Elastic fibres in the walls of the alveoli recoil.
B The diaphragm contracts.
C The external intercostal muscles contract.
D The internal intercostal muscles contract.
Your answer [1]
5 Which statement about the mammalian gas exchange system is correct?
A Cartilage supports the walls of the alveoli to prevent collapse during inspiration.
B Goblet cells line the alveoli and secrete mucus to trap dust particles and bacteria.
C Smooth muscle in the walls of bronchioles contracts to control air flow into alveoli.
D Trachea divide to form many small tracheoles that carry air to the alveoli.
Your answer [1]
Cambridge OCR 2026 Turn over
