AQA AS Level Biology Paper 1
Exam Questions and Answers
100% PASS
Define the primary structure of all proteins (2)—ANSWER-1- sequence of
amino acids
2- joined by peptide bonds
Define universal, non overlapping and degenerate (3)—ANSWER-1-
universal: Same codon/triplet always codes for the same amino acid
2- non overlapping: Each base only part of 1 triplet/codon OR
triplets/codons do not overlap
3- degenerate: More than 1 codon/triplet codes for each amino acid
Figure 1 shows transmission electron microscope image of a streptococcus
bacterium.
Describe how the appearance of the area containing DNA in a TEM image of
a eukaryotic cell would differ from that shown in figure 1
, (2)—ANSWER-1- nucleus
2- nucleolus OR nuclear membrane/envelope
3- mitochondria/chloroplast contain DNA
(can also say membrane bound nucleus for 2 marks)
describe one difference between the structure of DNA in a prokaryotic cells
and in a eukaryotic cell (1)—ANSWER-1- no introns
OR
circular not linear in prokaryotes
OR
not associated with proteins/histones
streptococcus bacteria can infect the lungs when air is breached in and
cause lung disease.
describe the mechanism of breathing that causes air to enter the lungs (3)—
ANSWER-1- diaphragm muscles contact AND diaphragm flattens
2- external intercostal muscles contract AND rib cage pulled up and out
3- causes volume increase AND pressure decrease in thoracic cavity to
below atmospheric pressure
© 2026 Copyright. All Rights Reserved. This document is
protected by copyright law, Copyrighted By Katelyn Whitman
Exam Questions and Answers
100% PASS
Define the primary structure of all proteins (2)—ANSWER-1- sequence of
amino acids
2- joined by peptide bonds
Define universal, non overlapping and degenerate (3)—ANSWER-1-
universal: Same codon/triplet always codes for the same amino acid
2- non overlapping: Each base only part of 1 triplet/codon OR
triplets/codons do not overlap
3- degenerate: More than 1 codon/triplet codes for each amino acid
Figure 1 shows transmission electron microscope image of a streptococcus
bacterium.
Describe how the appearance of the area containing DNA in a TEM image of
a eukaryotic cell would differ from that shown in figure 1
, (2)—ANSWER-1- nucleus
2- nucleolus OR nuclear membrane/envelope
3- mitochondria/chloroplast contain DNA
(can also say membrane bound nucleus for 2 marks)
describe one difference between the structure of DNA in a prokaryotic cells
and in a eukaryotic cell (1)—ANSWER-1- no introns
OR
circular not linear in prokaryotes
OR
not associated with proteins/histones
streptococcus bacteria can infect the lungs when air is breached in and
cause lung disease.
describe the mechanism of breathing that causes air to enter the lungs (3)—
ANSWER-1- diaphragm muscles contact AND diaphragm flattens
2- external intercostal muscles contract AND rib cage pulled up and out
3- causes volume increase AND pressure decrease in thoracic cavity to
below atmospheric pressure
© 2026 Copyright. All Rights Reserved. This document is
protected by copyright law, Copyrighted By Katelyn Whitman
