Oxford Cambridge and RSA
Examinations Foundation
GCSECombined Science B Twenty First
Century ScienceJ260/05: Biology (Higher
Tier) General Certificate of Secondary
Education( with marking scheme)
, Oxford Cambridge and RSA
Tuesday 16 May 2023 – Morning
GCSE (9–1) Combined Science B
(Twenty First Century Science)
J260/05 Biology (Higher Tier)
Time allowed: 1 hour 45 minutes
H
* 9 9 3 0 7 6 6 7 3 7 *
You must have:
• a ruler (cm/mm)
You can use:
• a scientific or graphical calculator
• an HB pencil
* J 2 6 0 0 5 *
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 95.
• 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.
© OCR 2023 [601/8690/2] OCR is an exempt Charity
DC (ST/CB) 329316/2 Turn over
, 2
1 A doctor uses a light microscope to look at the chromosomes in human body cells.
(a) The microscope is shown in the diagram.
Fine focus
Part C
Part A
Coarse focus
Part B
Mirror
(i) Draw lines to connect each part of the microscope with its correct name.
Part Name
Part A Eyepiece lens
Part B Objective lens
Part C Stage
[1]
(ii) The doctor uses steps A to D to look at the cells on a slide.
The steps are not in the correct order.
A Turn the coarse focus until the image is as clear as possible.
B Turn the fine focus until the image is as clear as possible.
C Adjust the mirror until the image is bright enough to see.
D Place the slide under the microscope.
Write the letters in the boxes to show the correct order of the steps.
One has been done for you.
D
[1]
(iii) The chromosomes in the cells are not clearly visible under the microscope.
Describe one thing the doctor can add to the slide to improve the visibility of the
chromosomes.
...................................................................................................................................... [1]
© OCR 2023
, 3
Humans have X and Y sex chromosomes.
(b) The Punnett square shows how X and Y chromosomes are inherited.
Sperm cells
Chromosomes X Y
X XX XY
Egg cells
X XX XY
(i) What is the probability that a fertilised egg will have the chromosomes XY?
Put a ring around the correct answer.
0 0.5 1 2 [1]
(ii) What is the expected ratio of XX to XY offspring?
Ratio = .................... : .................... [1]
(c) Describe how inheriting a Y chromosome causes the baby to be born with male
characteristics.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
.............................................................................................................................................. [2]
© OCR 2023 Turn over
Examinations Foundation
GCSECombined Science B Twenty First
Century ScienceJ260/05: Biology (Higher
Tier) General Certificate of Secondary
Education( with marking scheme)
, Oxford Cambridge and RSA
Tuesday 16 May 2023 – Morning
GCSE (9–1) Combined Science B
(Twenty First Century Science)
J260/05 Biology (Higher Tier)
Time allowed: 1 hour 45 minutes
H
* 9 9 3 0 7 6 6 7 3 7 *
You must have:
• a ruler (cm/mm)
You can use:
• a scientific or graphical calculator
• an HB pencil
* J 2 6 0 0 5 *
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 95.
• 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.
© OCR 2023 [601/8690/2] OCR is an exempt Charity
DC (ST/CB) 329316/2 Turn over
, 2
1 A doctor uses a light microscope to look at the chromosomes in human body cells.
(a) The microscope is shown in the diagram.
Fine focus
Part C
Part A
Coarse focus
Part B
Mirror
(i) Draw lines to connect each part of the microscope with its correct name.
Part Name
Part A Eyepiece lens
Part B Objective lens
Part C Stage
[1]
(ii) The doctor uses steps A to D to look at the cells on a slide.
The steps are not in the correct order.
A Turn the coarse focus until the image is as clear as possible.
B Turn the fine focus until the image is as clear as possible.
C Adjust the mirror until the image is bright enough to see.
D Place the slide under the microscope.
Write the letters in the boxes to show the correct order of the steps.
One has been done for you.
D
[1]
(iii) The chromosomes in the cells are not clearly visible under the microscope.
Describe one thing the doctor can add to the slide to improve the visibility of the
chromosomes.
...................................................................................................................................... [1]
© OCR 2023
, 3
Humans have X and Y sex chromosomes.
(b) The Punnett square shows how X and Y chromosomes are inherited.
Sperm cells
Chromosomes X Y
X XX XY
Egg cells
X XX XY
(i) What is the probability that a fertilised egg will have the chromosomes XY?
Put a ring around the correct answer.
0 0.5 1 2 [1]
(ii) What is the expected ratio of XX to XY offspring?
Ratio = .................... : .................... [1]
(c) Describe how inheriting a Y chromosome causes the baby to be born with male
characteristics.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
.............................................................................................................................................. [2]
© OCR 2023 Turn over
