5/26/25, 6:29 AM AQA A Level Biology - Paper 2 Flashcards | Quizlet
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AQA AAQA
LEVEL BIOLOGY
A Level Biology - Paper 2 PAPER 2
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AQA A-level Biology Practicals AQA A-Level Biology Paper 2 Biology (inheritance) Genetic
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Terms in this set (1518)
A gene mutation is a change in the sequence of base pairs in a DNA molecule that
What is a gene mutation?
may result in an altered polypeptide
How do mutations occur? Mutations occur continuously and spontaneously
As the DNA base sequences determines the sequence of amino acids that make up a
Why can gene mutations result in altered
protein, gene mutations can lead to a change in the polypeptide that the gene
polypeptides?
codes for.
What effect do most gene mutations have Most gene mutations do not alter the polypeptide or only alter it slightly so that its
and why? structure or function remains unaltered as genetic code is degenerate
Define degenerate A single amino acid may be coded for by multiple codons
What can mutations in the DNA base - Insertion, deletion or substitution of a nucleotide
sequence occur due to? - Inversion, duplication or translocation of a section of a gene
An insertion mutation is one that occurs when a nucleotide (thus containing a new
Describe insertion mutations
base) is randomly inserted into the DNA sequence
Insertion mutations change the triplet code that codes for an amino acid and
therefore may change the amino acid that would've been coded by the original base
What effect can insertion mutations have triplet as a new triplet of bases is created.
and why?
As they're frameshift mutations, insertion mutations also have a knock on effect by
changing the triplets further on in the DNA sequence.
Frameshift mutations may dramatically change the amino acid sequence produced
What are the potential consequences of
from this gene therefore the ability of the polypeptide to function due to the
frameshift mutations?
potential knock on effect they may have.
Deletion mutations are mutations that occur when a nucleotide (and therefore its
Describe deletion mutations and their
base) is randomly deleted from the DNA sequence and can also potentially change
effects
the amino acid that they would've coded for.
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, 5/26/25, 6:29 AM AQA A Level Biology - Paper 2 Flashcards | Quizlet
What type of mutations are deletion Also frameshift mutations so they may dramatically change the amino acid sequence
mutations? produced from this gene and therefore the ability of the polypeptide to function.
A substitution mutation is one that occurs when aw base in teh DNA sequence is
Describe substitution mutations
randomly swapped for a different base.
Unlike insertion or deletion mutations, a substitution mutation will only change the
What is the effect of a substitution
amino acid for the triplet in which the mutation occurs and there will be no knock on
mutation?
effect
What are the three types of substitution silent, missense, nonsense
mutation?
A silent mutation is when the mutation doesn't alter the amino acid sequence of the
What is a silent substitution mutation? polypeptide as certain codons may code for the same amino acid as the genetic
code is degenerate.
What is a missense mutation? the mutation alters a single amino acid in the polypeptide chain
Give an example of a missense mutation? sickle cell anemia
A nonsense mutation is a mutation that creates a premature stop codon (signal to the
cell to stop the translation of the mRNA into an amino acid sequence) causing the
What is a nonsense mutaiton?
polypeptide chain to be incompletely produced therefore affecting the final
protein's structure and function
Give an example of a nonsense mutation cystic fibrosis (although it can have alternate causes)
Where do inversion mutations of a gene Inversion mutations within a gene section usually occurs during crossing over in
section occur? meiosis.
The DNA of a single gene is cut in two places
The cut portion is inverted 180 degrees and rejoined to the same place within a
Describe the process of inversion
gene.
mutations in gene sections
As a result, a large section of the gene is backwards causing multiple amino acids to
be affected.
What do inversion mutations usually result Inversion mutations frequently result in non-functional proteins and in some cases an
in? entirely different protein altogether.
What is the harm potentially instigated by This mutation is usually harmful because the original gene can no longer be
inversion mutations? expressed from that chromosome
How can the effect of inversion mutations If the other chromosome in the pair carries a working gene then the effect of the
be reduced? mutation may be lessened
A duplication mutation is where a whole gene or a section of a gene is duplicated so
Describe duplication mutations
that two copies of the same gene or section appear on the same chromosome.
Original version of the gene remains intact so the mutation is not harmful
What are the effects of duplication The second copy of the gene can undergo mutations which can enable it to develop
mutations? new functions
Duplication mutations are an important source of evolutionary change
Give an example of a duplication mutation Alpha, beta and gamma Haemoglobin genes evolved due to duplication mutations
A portion of one non-homologous chromosome is transferred to another non-
homologous chromosome
describe translocation mutations
Translocation mutations involve a gene being cut into two places and that section of
the gene cuts off and attaches to a separate gene.
The result is that the cut gene is now non-functional due to having a section missing
What is the result of a translocation
and the gene that has gained the translocated section is also likely to be non-
mutation?
functional
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Science Biology Genetics Save
AQA AAQA
LEVEL BIOLOGY
A Level Biology - Paper 2 PAPER 2
COMPLETE GUIDE WITH 100% RATED 5.0 (1 review)
1500+ QUESTIONS AND ANSWERS |
Students also studied
GRADED A+ | 2025 LATEST UPDATED |
Flashcard sets Study guides Practice tests
AQA A-level Biology Practicals AQA A-Level Biology Paper 2 Biology (inheritance) Genetic
LATEST VERSIONS
28 terms 198 terms 26 terms 11 terms
aaf_11 Preview lpitman17 Preview Tyler_Hewitt74 Preview k_m
Terms in this set (1518)
A gene mutation is a change in the sequence of base pairs in a DNA molecule that
What is a gene mutation?
may result in an altered polypeptide
How do mutations occur? Mutations occur continuously and spontaneously
As the DNA base sequences determines the sequence of amino acids that make up a
Why can gene mutations result in altered
protein, gene mutations can lead to a change in the polypeptide that the gene
polypeptides?
codes for.
What effect do most gene mutations have Most gene mutations do not alter the polypeptide or only alter it slightly so that its
and why? structure or function remains unaltered as genetic code is degenerate
Define degenerate A single amino acid may be coded for by multiple codons
What can mutations in the DNA base - Insertion, deletion or substitution of a nucleotide
sequence occur due to? - Inversion, duplication or translocation of a section of a gene
An insertion mutation is one that occurs when a nucleotide (thus containing a new
Describe insertion mutations
base) is randomly inserted into the DNA sequence
Insertion mutations change the triplet code that codes for an amino acid and
therefore may change the amino acid that would've been coded by the original base
What effect can insertion mutations have triplet as a new triplet of bases is created.
and why?
As they're frameshift mutations, insertion mutations also have a knock on effect by
changing the triplets further on in the DNA sequence.
Frameshift mutations may dramatically change the amino acid sequence produced
What are the potential consequences of
from this gene therefore the ability of the polypeptide to function due to the
frameshift mutations?
potential knock on effect they may have.
Deletion mutations are mutations that occur when a nucleotide (and therefore its
Describe deletion mutations and their
base) is randomly deleted from the DNA sequence and can also potentially change
effects
the amino acid that they would've coded for.
https://quizlet.com/gb/916732560/aqa-a-level-biology-paper-2-flash-cards/ 1/7
, 5/26/25, 6:29 AM AQA A Level Biology - Paper 2 Flashcards | Quizlet
What type of mutations are deletion Also frameshift mutations so they may dramatically change the amino acid sequence
mutations? produced from this gene and therefore the ability of the polypeptide to function.
A substitution mutation is one that occurs when aw base in teh DNA sequence is
Describe substitution mutations
randomly swapped for a different base.
Unlike insertion or deletion mutations, a substitution mutation will only change the
What is the effect of a substitution
amino acid for the triplet in which the mutation occurs and there will be no knock on
mutation?
effect
What are the three types of substitution silent, missense, nonsense
mutation?
A silent mutation is when the mutation doesn't alter the amino acid sequence of the
What is a silent substitution mutation? polypeptide as certain codons may code for the same amino acid as the genetic
code is degenerate.
What is a missense mutation? the mutation alters a single amino acid in the polypeptide chain
Give an example of a missense mutation? sickle cell anemia
A nonsense mutation is a mutation that creates a premature stop codon (signal to the
cell to stop the translation of the mRNA into an amino acid sequence) causing the
What is a nonsense mutaiton?
polypeptide chain to be incompletely produced therefore affecting the final
protein's structure and function
Give an example of a nonsense mutation cystic fibrosis (although it can have alternate causes)
Where do inversion mutations of a gene Inversion mutations within a gene section usually occurs during crossing over in
section occur? meiosis.
The DNA of a single gene is cut in two places
The cut portion is inverted 180 degrees and rejoined to the same place within a
Describe the process of inversion
gene.
mutations in gene sections
As a result, a large section of the gene is backwards causing multiple amino acids to
be affected.
What do inversion mutations usually result Inversion mutations frequently result in non-functional proteins and in some cases an
in? entirely different protein altogether.
What is the harm potentially instigated by This mutation is usually harmful because the original gene can no longer be
inversion mutations? expressed from that chromosome
How can the effect of inversion mutations If the other chromosome in the pair carries a working gene then the effect of the
be reduced? mutation may be lessened
A duplication mutation is where a whole gene or a section of a gene is duplicated so
Describe duplication mutations
that two copies of the same gene or section appear on the same chromosome.
Original version of the gene remains intact so the mutation is not harmful
What are the effects of duplication The second copy of the gene can undergo mutations which can enable it to develop
mutations? new functions
Duplication mutations are an important source of evolutionary change
Give an example of a duplication mutation Alpha, beta and gamma Haemoglobin genes evolved due to duplication mutations
A portion of one non-homologous chromosome is transferred to another non-
homologous chromosome
describe translocation mutations
Translocation mutations involve a gene being cut into two places and that section of
the gene cuts off and attaches to a separate gene.
The result is that the cut gene is now non-functional due to having a section missing
What is the result of a translocation
and the gene that has gained the translocated section is also likely to be non-
mutation?
functional
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