)
AQA
A-Level
BIOLOGY
3.1 | Biological Molecules
1.5 Nucleic Acids - Structure and Replication
Time allowed
58 minutes
QUESTION PAPER
Score Percentage
/48 %
4.1 | CELL BIOLOGY | QUESTION PAPER 1 1
, The following figure represents part of a DNA molecule.
(a) Draw a box around a single nucleotide.
(1)
The table below shows the percentage of bases in each of the strands of a DNA
molecule.
DNA Percentage of each
strand base
A C G T
Strand 1 16
Strand 2 21 34
(b) Complete the table by adding the missing values.
(2)
(c) During replication, the two DNA strands separate and each acts as a template for
the production of a new strand. As new DNA strands are produced, nucleotides can
only be added in the 5’ to 3’ direction.
Use the figure in part (a) and your knowledge of enzyme action and DNA replication
to explain why new nucleotides can only be added in a 5’ to 3’ direction.
Page 9
PhysicsAndMathsTutor.com
AQA
A-Level
BIOLOGY
3.1 | Biological Molecules
1.5 Nucleic Acids - Structure and Replication
Time allowed
58 minutes
QUESTION PAPER
Score Percentage
/48 %
4.1 | CELL BIOLOGY | QUESTION PAPER 1 1
, The following figure represents part of a DNA molecule.
(a) Draw a box around a single nucleotide.
(1)
The table below shows the percentage of bases in each of the strands of a DNA
molecule.
DNA Percentage of each
strand base
A C G T
Strand 1 16
Strand 2 21 34
(b) Complete the table by adding the missing values.
(2)
(c) During replication, the two DNA strands separate and each acts as a template for
the production of a new strand. As new DNA strands are produced, nucleotides can
only be added in the 5’ to 3’ direction.
Use the figure in part (a) and your knowledge of enzyme action and DNA replication
to explain why new nucleotides can only be added in a 5’ to 3’ direction.
Page 9
PhysicsAndMathsTutor.com
