Please write clearly in block capitals.
Centre number Candidate number
Surname
Forename(s)
Candidate signature
I declare this is my own work.
INTERNATIONAL A-LEVEL
BIOLOGY (9610)
Unit 4 Control
Wednesday 11 January 2023 07:00 GMT Time allowed: 1 hour 30 minutes
Materials For Examiner’s Use
For this paper you must have:
• a ruler with millimetre measurements Question Mark
• a scientific calculator, which you are expected to use where appropriate. 1
2
Instructions
• Use black ink or black ball-point pen. 3
• Fill in the boxes at the top of this page. 4
• Answer all questions. 5
• You must answer the questions in the spaces provided. Do not write
outside the box around each page or on blank pages. 6
• If you need extra space for your answer(s), use the lined pages at the end of 7
this book. Write the question number against your answer(s).
TOTAL
• All working must be shown.
• Do all rough work in this book. Cross through any work you do not want
to be marked.
Information
• The marks for questions are shown in brackets.
• The maximum mark for this paper is 75.
*JAn23BL0401*
IB/M/Jan23/E10 BL04
, 2
Do not write
outside the
Answer all questions in the spaces provided. box
0 1 Motile bacteria have a flagellum and are able to move. These bacteria can show
chemotaxis.
0 1 . 1 Define the term chemotaxis.
[2 marks]
Two students investigate chemotaxis in motile, aerobic bacteria. Each student
prepares their own microscope slide.
The students:
• put a piece of photosynthetic green alga in water on a microscope slide
• put a coverslip over the alga
• add a drop of water containing the aerobic bacteria to the water under the coverslip
• leave the microscope slides in the light for 10 minutes.
The microscope slide is shown in Figure 1.
Figure 1
0 1 . 2 Complete Figure 2 to show the position of the aerobic bacteria after the slide has
been left in the light for 10 minutes.
[1 mark]
Figure 2
*02*
IB/M/Jan23/BL04
, 3
Do not write
outside the
0 1 . 3 Explain why the aerobic bacteria would be in the position you have drawn box
on Figure 2.
[3 marks]
0 1 . 4 When the students are waiting for 10 minutes, they keep their microscope slides in
different places.
The first student keeps her slide on the work bench in the light.
The second student keeps her slide on the stage of the microscope with the lamp
switched on.
Describe how an uncontrolled variable might affect the second student’s results.
[1 mark]
0 1 . 5 Mammals can respond to a stimulus with a reflex.
Define reflex.
[1 mark]
Question 1 continues on the next page
Turn over ►
*03*
IB/M/Jan23/BL04
, 4
Do not write
outside the
0 1 . 6 A reflex arc shows the pathway of a nerve impulse during a reflex. box
Tick () one box to show the correct pathway.
[1 mark]
motor relay sensory
Effector → → → → receptor
neurone neurone neurone
motor sensory relay
Effector → → → → receptor
neurone neurone neurone
relay motor sensory
Receptor → → → → effector
neurone neurone neurone
sensory relay motor
Receptor → → → → effector 9
neurone neurone neurone
*04*
IB/M/Jan23/BL04
Centre number Candidate number
Surname
Forename(s)
Candidate signature
I declare this is my own work.
INTERNATIONAL A-LEVEL
BIOLOGY (9610)
Unit 4 Control
Wednesday 11 January 2023 07:00 GMT Time allowed: 1 hour 30 minutes
Materials For Examiner’s Use
For this paper you must have:
• a ruler with millimetre measurements Question Mark
• a scientific calculator, which you are expected to use where appropriate. 1
2
Instructions
• Use black ink or black ball-point pen. 3
• Fill in the boxes at the top of this page. 4
• Answer all questions. 5
• You must answer the questions in the spaces provided. Do not write
outside the box around each page or on blank pages. 6
• If you need extra space for your answer(s), use the lined pages at the end of 7
this book. Write the question number against your answer(s).
TOTAL
• All working must be shown.
• Do all rough work in this book. Cross through any work you do not want
to be marked.
Information
• The marks for questions are shown in brackets.
• The maximum mark for this paper is 75.
*JAn23BL0401*
IB/M/Jan23/E10 BL04
, 2
Do not write
outside the
Answer all questions in the spaces provided. box
0 1 Motile bacteria have a flagellum and are able to move. These bacteria can show
chemotaxis.
0 1 . 1 Define the term chemotaxis.
[2 marks]
Two students investigate chemotaxis in motile, aerobic bacteria. Each student
prepares their own microscope slide.
The students:
• put a piece of photosynthetic green alga in water on a microscope slide
• put a coverslip over the alga
• add a drop of water containing the aerobic bacteria to the water under the coverslip
• leave the microscope slides in the light for 10 minutes.
The microscope slide is shown in Figure 1.
Figure 1
0 1 . 2 Complete Figure 2 to show the position of the aerobic bacteria after the slide has
been left in the light for 10 minutes.
[1 mark]
Figure 2
*02*
IB/M/Jan23/BL04
, 3
Do not write
outside the
0 1 . 3 Explain why the aerobic bacteria would be in the position you have drawn box
on Figure 2.
[3 marks]
0 1 . 4 When the students are waiting for 10 minutes, they keep their microscope slides in
different places.
The first student keeps her slide on the work bench in the light.
The second student keeps her slide on the stage of the microscope with the lamp
switched on.
Describe how an uncontrolled variable might affect the second student’s results.
[1 mark]
0 1 . 5 Mammals can respond to a stimulus with a reflex.
Define reflex.
[1 mark]
Question 1 continues on the next page
Turn over ►
*03*
IB/M/Jan23/BL04
, 4
Do not write
outside the
0 1 . 6 A reflex arc shows the pathway of a nerve impulse during a reflex. box
Tick () one box to show the correct pathway.
[1 mark]
motor relay sensory
Effector → → → → receptor
neurone neurone neurone
motor sensory relay
Effector → → → → receptor
neurone neurone neurone
relay motor sensory
Receptor → → → → effector
neurone neurone neurone
sensory relay motor
Receptor → → → → effector 9
neurone neurone neurone
*04*
IB/M/Jan23/BL04
