Oxford Cambridge and
RSA Examinations
GCEBiology BH422/03:
Practical skills in
biologyA Level with
marking scheme
, Oxford Cambridge and RSA
Wednesday 21 June 2023 – Morning
A Level Biology B (Advancing Biology)
H422/03 Practical skills in biology
Time allowed: 1 hour 30 minutes
You must have:
* 9 8 9 9 0 3 0 0 9 9 *
• the Insert (inside this document)
• 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.
© OCR 2023 [601/4720/9] OCR is an exempt Charity
DC (ST/SG) 317647/6 Turn over
, 2
1 Apoptosis is the programmed cell death of damaged or unwanted cells.
(a) Fig. 1.1 shows a transmission electron micrograph (TEM) of apoptosis of a leucocyte.
Fig. 1.1
A
D
B
C
(i) Name the following structures and processes shown in Fig. 1.1:
• the structure labelled A forming in the cell surface membrane
• the process occurring to the organelle labelled B
• the structure labelled C.
Structure A ........................................................................................................................
Process B ..........................................................................................................................
Structure C ........................................................................................................................
[3]
© OCR 2023
, 3
(ii) The magnification used to produce the TEM in Fig. 1.1 was × 20 000.
Calculate the actual diameter of the structure labelled D in Fig. 1.1.
Give your answer in standard form.
Diameter of structure D = ...................................................... m [2]
(b) A diagram of the cell cycle is shown in Fig. 1.2. The diagram shows a cell entering apoptosis
from the G2 phase.
Fig. 1.2
Apoptosis
M
G2
G1
S
(i) Suggest and explain why the cell in Fig. 1.2 entered apoptosis from G2.
...........................................................................................................................................
...................................................................................................................................... [1]
(ii) Outline a molecular mechanism that caused the cell to start apoptosis.
...........................................................................................................................................
...................................................................................................................................... [1]
© OCR 2023 Turn over
RSA Examinations
GCEBiology BH422/03:
Practical skills in
biologyA Level with
marking scheme
, Oxford Cambridge and RSA
Wednesday 21 June 2023 – Morning
A Level Biology B (Advancing Biology)
H422/03 Practical skills in biology
Time allowed: 1 hour 30 minutes
You must have:
* 9 8 9 9 0 3 0 0 9 9 *
• the Insert (inside this document)
• 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.
© OCR 2023 [601/4720/9] OCR is an exempt Charity
DC (ST/SG) 317647/6 Turn over
, 2
1 Apoptosis is the programmed cell death of damaged or unwanted cells.
(a) Fig. 1.1 shows a transmission electron micrograph (TEM) of apoptosis of a leucocyte.
Fig. 1.1
A
D
B
C
(i) Name the following structures and processes shown in Fig. 1.1:
• the structure labelled A forming in the cell surface membrane
• the process occurring to the organelle labelled B
• the structure labelled C.
Structure A ........................................................................................................................
Process B ..........................................................................................................................
Structure C ........................................................................................................................
[3]
© OCR 2023
, 3
(ii) The magnification used to produce the TEM in Fig. 1.1 was × 20 000.
Calculate the actual diameter of the structure labelled D in Fig. 1.1.
Give your answer in standard form.
Diameter of structure D = ...................................................... m [2]
(b) A diagram of the cell cycle is shown in Fig. 1.2. The diagram shows a cell entering apoptosis
from the G2 phase.
Fig. 1.2
Apoptosis
M
G2
G1
S
(i) Suggest and explain why the cell in Fig. 1.2 entered apoptosis from G2.
...........................................................................................................................................
...................................................................................................................................... [1]
(ii) Outline a molecular mechanism that caused the cell to start apoptosis.
...........................................................................................................................................
...................................................................................................................................... [1]
© OCR 2023 Turn over
