Please check the examination details below before entering your candidate information
Candidate surname Other names
Centre Number Candidate Number
Pearson Edexcel International GCSE (9–1)
Monday 3 November 2025
Morning (Time: 2 hours) Paper
reference 4BI1/1B 4SD0/1B
Biology
UNIT: 4BI1
Science (Double Award) 4SD0
PAPER: 1B
You must have: Total Marks
Calculator, ruler
Instructions
•• Use black ink or ball-point pen.
If pencil is used for diagrams/sketches/graphs it must be dark (HB or B).
• 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.
• Show all the steps in any calculations and state the units.
Information
•• The total mark for this paper is 110.
The marks for each question are shown in brackets
– use this as a guide as to how much time to spend on each question.
Advice
•• Read each question carefully before you start to answer it.
Write your answers neatly and in good English.
•• Try to answer every question.
Check your answers if you have time at the end.
Turn over
P75943RA
©2025 Pearson Education Ltd.
M:1/1/1/1/1/1/1/1/1/1/1/1/1/1
*P75943RA0128*
, Answer ALL questions. Write your answers in the spaces provided.
Some questions must be answered with a cross in a box . If you change your mind about an
DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA
answer, put a line through the box and then mark your new answer with a cross .
1 An Amoeba is a microscopic single‑celled organism that lives in pond water.
The diagram shows an Amoeba with some structures labelled.
X
S
R
Q
Y
P
(Source: © Vecton/Shutterstock)
(a) (i) Which structure is the nucleus?
(1)
A P
B Q
C R
D S
(ii) Which structure is the cytoplasm?
(1)
A P
B Q
C R
D S
(iii) Which structure contains chromosomes?
(1)
A P
B Q
C R
D S
2
*P75943RA0228*
, (iv) The magnification of the diagram is ×65.
Calculate the actual length of the Amoeba from X to Y.
DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA
[1000 μm = 1 mm]
(2)
length = .................................................. . . . . . . . . . . . . μm
(b) Give three differences in structure between an Amoeba and a virus.
(3)
1 .. . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................................ . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................................................................................................... .. . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................................ . . . . . . . . . . . . . . . . . . . .
2 .. . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................................ . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................................................................................................... .. . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................................ . . . . . . . . . . . . . . . . . . . .
3 .. . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................................ . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................................................................................................... .. . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................................ . . . . . . . . . . . . . . . . . . . .
(Total for Question 1 = 8 marks)
3
*P75943RA0328* Turn over
, 2 A teacher uses this apparatus to investigate the effect of concentration of a substance
on the rate of diffusion.
DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA
cotton wool with drops
of ammonia solution damp red litmus paper rubber bung
4 cm 8 cm 12 cm 16 cm 20 cm 24 cm
This is the teacher’s method.
• place six small squares of damp red litmus paper in a glass tube at 4 cm intervals
• put the glass tube in a fume cupboard
• add 1 drop of ammonia solution to some cotton wool
• place the cotton wool at one end of the glass tube
• close the tube with two bungs
• record the time taken for the ammonia to change the colour of each square of
litmus paper
The teacher repeats the method with 3 drops of ammonia solution instead of 1 drop.
(a) State what is meant by the term diffusion.
(1)
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ ................ . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ ................ . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ ................ . . . . . . . . . . . . . . . . . . . .
(b) The table gives the teacher’s results.
Number of Time taken for litmus to change colour in seconds
drops of
ammonia solution 4 cm 8 cm 12 cm 16 cm 20 cm 24 cm
1 8 15 20 25 31 38
3 2 6 11 14 17 22
4
*P75943RA0428*
Candidate surname Other names
Centre Number Candidate Number
Pearson Edexcel International GCSE (9–1)
Monday 3 November 2025
Morning (Time: 2 hours) Paper
reference 4BI1/1B 4SD0/1B
Biology
UNIT: 4BI1
Science (Double Award) 4SD0
PAPER: 1B
You must have: Total Marks
Calculator, ruler
Instructions
•• Use black ink or ball-point pen.
If pencil is used for diagrams/sketches/graphs it must be dark (HB or B).
• 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.
• Show all the steps in any calculations and state the units.
Information
•• The total mark for this paper is 110.
The marks for each question are shown in brackets
– use this as a guide as to how much time to spend on each question.
Advice
•• Read each question carefully before you start to answer it.
Write your answers neatly and in good English.
•• Try to answer every question.
Check your answers if you have time at the end.
Turn over
P75943RA
©2025 Pearson Education Ltd.
M:1/1/1/1/1/1/1/1/1/1/1/1/1/1
*P75943RA0128*
, Answer ALL questions. Write your answers in the spaces provided.
Some questions must be answered with a cross in a box . If you change your mind about an
DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA
answer, put a line through the box and then mark your new answer with a cross .
1 An Amoeba is a microscopic single‑celled organism that lives in pond water.
The diagram shows an Amoeba with some structures labelled.
X
S
R
Q
Y
P
(Source: © Vecton/Shutterstock)
(a) (i) Which structure is the nucleus?
(1)
A P
B Q
C R
D S
(ii) Which structure is the cytoplasm?
(1)
A P
B Q
C R
D S
(iii) Which structure contains chromosomes?
(1)
A P
B Q
C R
D S
2
*P75943RA0228*
, (iv) The magnification of the diagram is ×65.
Calculate the actual length of the Amoeba from X to Y.
DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA
[1000 μm = 1 mm]
(2)
length = .................................................. . . . . . . . . . . . . μm
(b) Give three differences in structure between an Amoeba and a virus.
(3)
1 .. . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................................ . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................................................................................................... .. . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................................ . . . . . . . . . . . . . . . . . . . .
2 .. . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................................ . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................................................................................................... .. . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................................ . . . . . . . . . . . . . . . . . . . .
3 .. . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................................ . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................................................................................................... .. . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................................ . . . . . . . . . . . . . . . . . . . .
(Total for Question 1 = 8 marks)
3
*P75943RA0328* Turn over
, 2 A teacher uses this apparatus to investigate the effect of concentration of a substance
on the rate of diffusion.
DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA
cotton wool with drops
of ammonia solution damp red litmus paper rubber bung
4 cm 8 cm 12 cm 16 cm 20 cm 24 cm
This is the teacher’s method.
• place six small squares of damp red litmus paper in a glass tube at 4 cm intervals
• put the glass tube in a fume cupboard
• add 1 drop of ammonia solution to some cotton wool
• place the cotton wool at one end of the glass tube
• close the tube with two bungs
• record the time taken for the ammonia to change the colour of each square of
litmus paper
The teacher repeats the method with 3 drops of ammonia solution instead of 1 drop.
(a) State what is meant by the term diffusion.
(1)
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ ................ . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ ................ . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ ................ . . . . . . . . . . . . . . . . . . . .
(b) The table gives the teacher’s results.
Number of Time taken for litmus to change colour in seconds
drops of
ammonia solution 4 cm 8 cm 12 cm 16 cm 20 cm 24 cm
1 8 15 20 25 31 38
3 2 6 11 14 17 22
4
*P75943RA0428*
