Tuesday 16 June 2026 – Morning
A Level Biology B (Advancing Biology)
H422/03 Practical skills in biology
Time allowed: 1 hour 30 minutes
You must have:
* 2 8 7 0 2 6 4 1 7 5 *
• a ruler (cm/mm)
You can use:
• a scientific or graphical calculator
* H 4 2 2 0 3 *
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 pages 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 60.
• 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 20 pages.
ADVICE
• Read each question carefully before you start your answer.
© Cambridge OCR 2026 [601/4720/9] Cambridge OCR is an exempt Charity
DC (CJ/SG) 372501/4 Turn over
, 2
1 Mitosis and meiosis are both forms of nuclear division.
(a) This is a photomicrograph of onion plant cells in different stages of the cell cycle. Four of the cells
are labelled A, B, C and D.
D
A
C
B
(i) State the sequence of letters that shows the correct order of stages during mitosis.
Assume that prophase is the first stage of mitosis.
..................... ..................... ..................... .....................
[2]
(ii) A student prepares a sample of onion plant tissue and sets up a light microscope in order to
visualise an image similar to the one in the photomicrograph.
The student writes this method:
• Peel off a layer of cells from the onion tissue and place it on a microscope slide.
• Use a pipette to add stain at one end of the layer of cells.
• Place a cover slip over the sample.
• Place the slide on the microscope stage and select the objective lens with the lowest power.
• Turn the coarse adjustment knobs until the lens is slightly above the slide.
• Turn the coarse adjustment knobs again, so that the lens moves away from the stage, until
the image is in focus.
© Cambridge OCR 2026
, 3
Outline four improvements to the method written by the student.
1 .......................................................................................................................................................
..........................................................................................................................................................
2 .......................................................................................................................................................
..........................................................................................................................................................
3 .......................................................................................................................................................
..........................................................................................................................................................
4 .......................................................................................................................................................
..........................................................................................................................................................
[4]
(b) This is a photomicrograph of a cell from a Lilium plant in a stage of meiosis.
X
(i) State the stage of meiosis shown in the photomicrograph.
..................................................................................................................................................... [1]
(ii) The cell in the photomicrograph is in the late part of the stage stated in (b)(i).
Outline the evidence for this observation.
..........................................................................................................................................................
..................................................................................................................................................... [1]
© Cambridge OCR 2026 Turn over
A Level Biology B (Advancing Biology)
H422/03 Practical skills in biology
Time allowed: 1 hour 30 minutes
You must have:
* 2 8 7 0 2 6 4 1 7 5 *
• a ruler (cm/mm)
You can use:
• a scientific or graphical calculator
* H 4 2 2 0 3 *
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 pages 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 60.
• 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 20 pages.
ADVICE
• Read each question carefully before you start your answer.
© Cambridge OCR 2026 [601/4720/9] Cambridge OCR is an exempt Charity
DC (CJ/SG) 372501/4 Turn over
, 2
1 Mitosis and meiosis are both forms of nuclear division.
(a) This is a photomicrograph of onion plant cells in different stages of the cell cycle. Four of the cells
are labelled A, B, C and D.
D
A
C
B
(i) State the sequence of letters that shows the correct order of stages during mitosis.
Assume that prophase is the first stage of mitosis.
..................... ..................... ..................... .....................
[2]
(ii) A student prepares a sample of onion plant tissue and sets up a light microscope in order to
visualise an image similar to the one in the photomicrograph.
The student writes this method:
• Peel off a layer of cells from the onion tissue and place it on a microscope slide.
• Use a pipette to add stain at one end of the layer of cells.
• Place a cover slip over the sample.
• Place the slide on the microscope stage and select the objective lens with the lowest power.
• Turn the coarse adjustment knobs until the lens is slightly above the slide.
• Turn the coarse adjustment knobs again, so that the lens moves away from the stage, until
the image is in focus.
© Cambridge OCR 2026
, 3
Outline four improvements to the method written by the student.
1 .......................................................................................................................................................
..........................................................................................................................................................
2 .......................................................................................................................................................
..........................................................................................................................................................
3 .......................................................................................................................................................
..........................................................................................................................................................
4 .......................................................................................................................................................
..........................................................................................................................................................
[4]
(b) This is a photomicrograph of a cell from a Lilium plant in a stage of meiosis.
X
(i) State the stage of meiosis shown in the photomicrograph.
..................................................................................................................................................... [1]
(ii) The cell in the photomicrograph is in the late part of the stage stated in (b)(i).
Outline the evidence for this observation.
..........................................................................................................................................................
..................................................................................................................................................... [1]
© Cambridge OCR 2026 Turn over
