AQA A Level Biology Paper 1 June
2018 Exam Question & Answers 2025
When preparing the cells for observation the scientist
placed them in a solution that had a slightly higher (less
negative) water potential than the cytoplasm. This did not
cause the cells to burst but moved the chromosomes
further apart in order to reduce the overlapping of the
chromosomes when observed with an optical microscope.
Suggest how this procedure moved the chromosomes
apart. [2 marks] - CORRECT ANSWERS ✔✔water
moves into the cells/ cytoplasm by osmosis
cell/ cytoplasm gets bigger
The dark stain used on the chromosomes binds more to
some areas of the chromosomes than others, giving the
chromosomes a striped appearance.
Suggest one way the structure of the chromosome could
differ along its length to result in the stain binding more
in some areas.[1 mark] - CORRECT ANSWERS
✔✔differences in base sequence
What is a homologous pair of chromosomes? [1 mark] -
CORRECT ANSWERS ✔✔chromosomes that carry the
same genes
, AQA A Level Biology Paper 1 June
2018 Exam Question & Answers 2025
Give two ways in which the arrangement of prokaryotic
DNA is different from the arrangement of the human DNA.
[2 marks] - CORRECT ANSWERS ✔✔(Prokaryotic
DNA) is
1. Circular (as opposed to linear)
2. Not associated with proteins/ histones
3. Only one molecule/ piece of DNA
Describe the method the student would have used to
obtain the results in Figure 3. Start after all the cubes of
potatoes have been cut. Also consider variables he should
have controlled. [3 marks] - CORRECT ANSWERS
✔✔Method to ensure all the cut surfaces of the eight
cubes are exposed to the sucrose solution
method of controlling temperature
method of drying cubes before measuring
measure of mass of tubes at stated time intervals
2018 Exam Question & Answers 2025
When preparing the cells for observation the scientist
placed them in a solution that had a slightly higher (less
negative) water potential than the cytoplasm. This did not
cause the cells to burst but moved the chromosomes
further apart in order to reduce the overlapping of the
chromosomes when observed with an optical microscope.
Suggest how this procedure moved the chromosomes
apart. [2 marks] - CORRECT ANSWERS ✔✔water
moves into the cells/ cytoplasm by osmosis
cell/ cytoplasm gets bigger
The dark stain used on the chromosomes binds more to
some areas of the chromosomes than others, giving the
chromosomes a striped appearance.
Suggest one way the structure of the chromosome could
differ along its length to result in the stain binding more
in some areas.[1 mark] - CORRECT ANSWERS
✔✔differences in base sequence
What is a homologous pair of chromosomes? [1 mark] -
CORRECT ANSWERS ✔✔chromosomes that carry the
same genes
, AQA A Level Biology Paper 1 June
2018 Exam Question & Answers 2025
Give two ways in which the arrangement of prokaryotic
DNA is different from the arrangement of the human DNA.
[2 marks] - CORRECT ANSWERS ✔✔(Prokaryotic
DNA) is
1. Circular (as opposed to linear)
2. Not associated with proteins/ histones
3. Only one molecule/ piece of DNA
Describe the method the student would have used to
obtain the results in Figure 3. Start after all the cubes of
potatoes have been cut. Also consider variables he should
have controlled. [3 marks] - CORRECT ANSWERS
✔✔Method to ensure all the cut surfaces of the eight
cubes are exposed to the sucrose solution
method of controlling temperature
method of drying cubes before measuring
measure of mass of tubes at stated time intervals
