A-LEVEL BIOLOGY Name:
Practice Paper 2 Maximum marks: 91 Time Allowed: 2 hours
These questions are from past papers covering topics and skills based on the advance
information to help you prepare for the exams this summer.
Answer all questions in the spaces provided.
1 A student investigated the rate of anaerobic respiration in yeast. She put 5 g of yeast
into a glucose solution and placed this mixture in the apparatus shown in the figure
below.
She then recorded the total volume of gas collected every 10 minutes for 1 hour.
(a) Explain why a layer of oil is required in this investigation.
_____________________________________________________________
_____________________________________________________________
(1)
(b) The student’s results are shown in the following table.
Total volume of gas
Time / minutes
collected / cm3
10 0.3
20 0.9
30 1.9
40 3.1
50 5.0
60 5.2
Page 1
This document is licensed to Haggerston School - MB260045
, (i) Calculate the rate of gas production in cm3 g–1 min–1 during the first 40
minutes of this investigation. Show your working.
Answer = ____________________ cm3 g–1 min–1
(2)
(ii) Suggest why the rate of gas production decreased between 50 and 60
minutes.
__________________________________________________________
__________________________________________________________
__________________________________________________________
__________________________________________________________
(1)
(iii) Yeast can also respire aerobically. The student repeated the investigation
with a fresh sample of yeast in glucose solution, but without the oil. All other
conditions remained the same.
Explain what would happen to the volume of gas in the syringe if the yeast
were only respiring aerobically.
__________________________________________________________
__________________________________________________________
__________________________________________________________
__________________________________________________________
(2)
(c) Respiration produces more ATP per molecule of glucose in the presence of
oxygen than it does when oxygen is absent. Explain why.
_____________________________________________________________
_____________________________________________________________
_____________________________________________________________
_____________________________________________________________
(2)
(Total 8 marks)
Page 2
This document is licensed to Haggerston School - MB260045
, 2 (a) A myelinated axon conducts impulses faster than a non-myelinated axon.
Explain this difference.
_____________________________________________________________
_____________________________________________________________
_____________________________________________________________
_____________________________________________________________
_____________________________________________________________
(3)
Doctors investigated the relationship between myelin in brain tissue and different types
of dementia. All types of dementia involve loss of mental ability.
The doctors measured the mean amount of myelin in samples of brain tissue from:
• a control group of 12 people without dementia
• 20 people with vascular dementia (VaD)
• 19 people with Alzheimer's dementia (AD)
• 31 people with Lewy body dementia (LD).
The doctors’ results are shown in the figure. The vertical bars show standard errors.
Group of people
(b) The doctors used a statistical test to compare the results for AD and LD.
They obtained a value for P of 0.047.
What does this result show about the difference between the means for AD and LD?
Use the words probability and chance in your answer.
_____________________________________________________________
_____________________________________________________________
_____________________________________________________________
(2)
Page 3
This document is licensed to Haggerston School - MB260045
Practice Paper 2 Maximum marks: 91 Time Allowed: 2 hours
These questions are from past papers covering topics and skills based on the advance
information to help you prepare for the exams this summer.
Answer all questions in the spaces provided.
1 A student investigated the rate of anaerobic respiration in yeast. She put 5 g of yeast
into a glucose solution and placed this mixture in the apparatus shown in the figure
below.
She then recorded the total volume of gas collected every 10 minutes for 1 hour.
(a) Explain why a layer of oil is required in this investigation.
_____________________________________________________________
_____________________________________________________________
(1)
(b) The student’s results are shown in the following table.
Total volume of gas
Time / minutes
collected / cm3
10 0.3
20 0.9
30 1.9
40 3.1
50 5.0
60 5.2
Page 1
This document is licensed to Haggerston School - MB260045
, (i) Calculate the rate of gas production in cm3 g–1 min–1 during the first 40
minutes of this investigation. Show your working.
Answer = ____________________ cm3 g–1 min–1
(2)
(ii) Suggest why the rate of gas production decreased between 50 and 60
minutes.
__________________________________________________________
__________________________________________________________
__________________________________________________________
__________________________________________________________
(1)
(iii) Yeast can also respire aerobically. The student repeated the investigation
with a fresh sample of yeast in glucose solution, but without the oil. All other
conditions remained the same.
Explain what would happen to the volume of gas in the syringe if the yeast
were only respiring aerobically.
__________________________________________________________
__________________________________________________________
__________________________________________________________
__________________________________________________________
(2)
(c) Respiration produces more ATP per molecule of glucose in the presence of
oxygen than it does when oxygen is absent. Explain why.
_____________________________________________________________
_____________________________________________________________
_____________________________________________________________
_____________________________________________________________
(2)
(Total 8 marks)
Page 2
This document is licensed to Haggerston School - MB260045
, 2 (a) A myelinated axon conducts impulses faster than a non-myelinated axon.
Explain this difference.
_____________________________________________________________
_____________________________________________________________
_____________________________________________________________
_____________________________________________________________
_____________________________________________________________
(3)
Doctors investigated the relationship between myelin in brain tissue and different types
of dementia. All types of dementia involve loss of mental ability.
The doctors measured the mean amount of myelin in samples of brain tissue from:
• a control group of 12 people without dementia
• 20 people with vascular dementia (VaD)
• 19 people with Alzheimer's dementia (AD)
• 31 people with Lewy body dementia (LD).
The doctors’ results are shown in the figure. The vertical bars show standard errors.
Group of people
(b) The doctors used a statistical test to compare the results for AD and LD.
They obtained a value for P of 0.047.
What does this result show about the difference between the means for AD and LD?
Use the words probability and chance in your answer.
_____________________________________________________________
_____________________________________________________________
_____________________________________________________________
(2)
Page 3
This document is licensed to Haggerston School - MB260045
