AQA AS BIOLOGY Paper 1 QP 2021
Please write clearly in block capitals.
Centre number Candidate number
Surname
Y
Forename(s)
Candidate signatu re
AS
BIOLOGY
Paper 1
Time allowed: 1 hour 30 minutes
Materials
For this paper you must have: For Examiner’s Use
a ruler with millimetre measurements Question Mark
a scientific calculator.
1
Instructions 2
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).
8
Show all your working.
Do all rough work in this book. Cross through any work you do not want 9
to be marked. TOTAL
Information
The marks for the questions are shown in brackets.
The maximum mark for this paper is 75.
*JUN217401101*
IB/M/Jun21/E17 7401/1
, 2
Do not write
outside the
Answer all questions in the spaces provided. box
0 1 Figure 1 shows part of a DNA molecule.
Figure 1
0 1
.1 Name the type of bond between:
[2 marks]
complementary base pairs
adjacent nucleotides in a DNA strand
0 1
.2 The length of a gene is described as the number of nucleotide base pairs it contains.
3
Use information in Figure 1 to calculate the length of a gene containing 4.38 ×10
base pairs.
[2 marks]
Answer nm
*02*
IB/M/Jun21/7401/1
, 3
Do not write
outside the
box
0 1 .3 Describe two differences between the structure of a tRNA molecule and the
structure of an mRNA molecule.
[2 marks]
1
2
. In a eukaryotic cell, the structure of the mRNA used in translation is different from
the structure of the pre-mRNA produced by transcription.
Describe and explain a difference in the structure of these mRNA molecules.
[2 marks]
8
Turn over for the next question
Turn over ►
*03*
IB/M/Jun21/7401/1
, 4
Do not write
outside the
0 2 Figure 2 shows the structure of the human immunodeficiency virus (HIV). box
Figure 2
0 2
.1 Name structures A and B.
[2 marks]
A
B
. Describe how HIV is replicated.
[4 marks]
6
*04*
IB/M/Jun21/7401/1
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