Mutation Flashcards
(175 cards)
1
Q
refers to a genetic alteration where a single nucleotide — one of the basic
building blocks of DNA or RNA — is changed.
A
point mutation
2
Q
point mutation can be
A
substitution
insertion
deletion
3
Q
are among the simplest and most common types of
genetic mutations
A
point moutation
4
Q
point mutation effects can vary depending on:
A
where the mutation occurs
where it alters the amino acid sequence
whether it affects important regulatory signals
5
Q
are fundamental to biological evolution, because they introduce new genetic
variations into populations
A
point mutations
6
Q
The primary mechanism behind point mutations involves errors during DNA ___
A
replications
7
Q
When a cell copies its DNA to divide, ___ ___ enzymes synthesize a new
complementary strand. Sometimes, these polymerases make mistakes — inserting an incorrect
nucleotide opposite a template base
A
DNA polymerase
8
Q
.Other causes of point mutations include:
A
mutagens
radiation
spontaneous mutations
9
Q
Certain chemicals (like nitrous acid) can modify DNA bases, leading to
mispairing.
A
mutagens
10
Q
deaminates adenine, which then pairs with
cytosine instead of thymine.
A
nitrous acid
11
Q
can cause the formation of thymine dimers, interfering with
normal base pairing and leading to mutations during DNA repair.
A
ultraviolet light
12
Q
DNA bases can naturally undergo chemical changes (like __, turning
cytosine into uracil), causing mispairing during replication.
A
deamination
13
Q
If cytosine (C) loses an amine group, it becomes uracil (U). When replication occurs, U pairs
with adenine (A) instead of guanine (G). If this mistake is not repaired, a C-G base pair will be
replaced by a T-A pair in future generations of cells — a permanent point mutation.
what mechanism
A
deamination
14
Q
These mutations change the nucleotide sequence but do not alter the resulting
amino acid because of the redundancy of the genetic code (e.g., both GAA and
GAG code for glutamic acid). Therefore, the protein’s function remains
unaffected.
A
silent mutations
15
Q
Here, the mutation causes a single amino acid change in the protein. This
change may have little effect, or it may alter protein folding, stability, or function
significantly.
A
missennse mutation
16
Q
example of missense mutation
A
sickle cell anemia
17
Q
in sickle cell anemia, missense mutation occurs where __ is replaced by ___ in hemoglobin
A
glutamic acid
valine
18
Q
In this case, the point mutation converts a codon that encodes an amino acid into
a stop codon (e.g., UAU [tyrosine] mutates to UAA [stop]). This results in a
prematurely truncated protein, often leading to loss of function and serious
disease.
A
nonsense mutations
19
Q
This can alter the codon (three-nucleotide sequence) and potentially change the amino
acid it codes for, or it may have no effect
type of point mutation
A
substitution
20
Q
substitution are further categorized into:
A
missense
nonsense
silent mutations
21
Q
happens when one nucleotide is replaced by another
A
substitution mutation
22
Q
which result in a different amino acid
A
missense mutation
23
Q
which create a premature stop codon
A
nonsense mutation
24
Q
which do not change the
amino acid due to redundancy in the genetic code
A
silent mutation
25
adds a new nucleotide to the DNA sequence
insertion
26
can disrupt the reading
frame (how codons are read) and lead to a frameshift mutation
insertion
27
can dramatically change the encoded protein
is a type of genetic mutation where the addition or deletion of nucleotides in a DNA sequence disrupts the reading frame, leading to a completely different protein sequence from the intended one.
frameshift mutation
28
occurs when a new nucleotide is added into the DNA sequence. This
can shift the reading frame of the genetic code, leading to what is called a frameshift mutation.
insertion mutation
29
changes how codons are read during translation, often resulting in a completely
different and nonfunctional protein
frameshift
30
removes a nucleotide from the DNA sequence
deletion
31
- Like insertions, __can also cause frameshift mutations, altering the reading frame
and the encoded protein
deletion
32
involves the removal of a nucleotide from the DNA sequence. Like
insertions, deletions can cause a frameshift mutation if the number of removed nucleotides is
not a multiple of three. T
deletion
33
arise intrinsically from the DNA replication process. Despite
replication's high fidelity attributed to the proofreading capability of DNA polymerase, errors may
occasionally occur.
spontaneous mutation
34
spontaneous mutations may result from ___
tautomeric shifts
35
wherein bases temporarily
assume uncommon chemical forms that pair incorrectly, such as thymine pairing with guanine
instead of adenine.
tautomeric shifts
36
is another factor, wherein the elimination of an amino group,
such as the conversion of cytosine to uracil, results in mispairing during replication
deamination
37
the elimination of purine bases (adenine or guanine), creates vacant
sites in the DNA strand, which may lead to the incorporation of incorrect nucleotides during the
repair process
depurination
38
Although certain mutations are rectified by __ mechanisms, uncorrected
discrepancies can lead to point mutations, which may influence gene function based on their
position and characteristics
repair
39
are initiated by external environmental mutagens, encompassing various
chemical agents and types of radiation.
induced mutations
40
chemically alter bases, impairing their capacity for proper pairing
alkylating agents
41
can inflict damage on DNA through various mechanisms: ultraviolet (UV) light induces the
formation of thymine dimers, which distort the DNA helix and impede replication, whereas
ionizing radiation (such as X-rays or gamma rays) can sever the sugar-phosphate backbone,
resulting in significant damage and elevated mutation rates
radiation
42
induces the
formation of thymine dimers, which distort the DNA helix and impede replication
UV light
43
can sever the sugar-phosphate backbone,
resulting in significant damage and elevated mutation rates
ionizing radiation (xrays, gamma rays)
44
including transposons and viruses, can also induce genetic mutations.
biological agents
45
commonly known as "jumping genes," are mobile genetic elements capable of
randomly integrating into the genome.
transposons
46
This insertion may interfere with coding sequences or
regulatory regions, potentially silencing or misregulating genes. In certain instances, segments
of genes may be transported, resulting in rearrangements
transposons
47
can
incorporate their genetic material into the host genome during infection
viruses
48
This integration may
disrupt normal gene function, activate oncogenes, or inactivate tumor suppressor genes,
contingent upon the insertion site. Over time, such insertions may accumulate and lead to
genetic variation or disease
retroviruses
49
mutations that Doesn’t affect the organism's overall function.
neutral mutations
50
For instance, a change from the codon GAA to
GAG still codes for the amino acid glutamic acid. Since the protein stays the same, there’s no
effect on the organism
silent mutations
51
Although RARE, it can provide an advantage to the organism’s survival or reproduction.
beneficial mutations
52
mutation provides resistance to HIV infection
CCR5-Δ32
53
People with this mutation have
a defective CCR5 receptor on their white blood cells, which HIV normally uses to enter the cell.
As a result, individuals with this mutation are less likely to get infected.
CCR5-Δ32 mutation
54
More common and can lead to significant problems and is associated with various genetic
diseases
harmful mutations
55
are common in point mutations because random changes are more
likely to disrupt important protein functions than to improve them.
harmful mutations
56
are changes that affect a single nucleotide base in the DNA sequence
point mutations
57
Two of the most common and reliable
techniques used for detecting point mutations are
PCR
DNA sequencing
58
is a molecular biology technique used to amplify specific segments of DNA
PCR
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is the process of determining the exact order of nucleotides in a DNA
molecule
DNA sequecing
60
This technique allows scientists to read the genetic code directly and identify any
alterations, including point mutations.
DNA sequencing
61
Modern sequencing technologies, such as ___ and __have made it possible to analyze entire
genomes with high accuracy. DNA sequencing is considered the gold standard for detecting
mutations at the molecular level
sanger sequencing
next generation sequencing (NGS)
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. For instance, a single point mutation in the HBB gene causes
sickle cell anemia
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disorder affecting red blood cells
sickle cell anemia
64
Point mutations serve as genetic markers that are unique to individuals. In forensic
science, they are used in
DNA fingerprinting
65
a technique that helps identify individuals from
biological evidence like blood, hair, or skin
DNA finger printing
66
which map the evolutionary relationships among organisms.
Mutations accumulate over generations
phylogenetic trees
67
heritable changes in
genetic information.
mutations
68
mutations came from the latin word
mutare
69
involve changes in one
or a few nucleotides
point mutations
70
mutare means
to change
71
involve changes in the
number or structure of
chromosomes
chromosomal mutation
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why do mutations occur?
Errors in meiotic or mitotic processes
DNA damage and repair errors
Recombination mistakes
Chromosomal instability
73
involve changes in the
structure or arrangement
of chromosomes
structural mutations
74
involve changes in the
number of
chromosomes in a cel
numerical mutations
75
4 types of structural mutation
deletions
duplication
inversoin
translocation
76
__ involves the
loss of all or part of
a chromosome.
deletions
77
example of deletions
5p- syndrome (cri-du-chat syndrome)
78
produces an extra
copy of all or part of
a chromosome
duplications
79
example of duplication
Charcot
Marie-Tooth disease
type 1A (CMT1A).
80
short arm of this chromosome that is duplicated
chromosome 17
81
occurs when a segment
of a chromosome breaks
off, flips around, and
reattaches in the reverse
direction.
inversion
82
disease for inversion chromosomal mutation
hemophilia A
83
Includes
centromere,
which
is
the
the
central part of
the chromosome.
pericentric inversion
84
does not involve
the centromere
paracentric inversion
85
a segment of one
chromosome breaks off
and becomes attached
to a different
chromosome
translocation
86
example of disease caused by translocation
chronic myeloid leukemia
87
CML is also known as
philadelphia chromosome
88
Two non-homologous
chromosomes exchange
segments of DNA with
each other.
reciprocal inversion
89
The long arms of two
chromosomes fuse to form
a single chromosome, and
the short arms are lost
robertsonian translocaton
90
This is the change in chromosome number deviated from the
standard chromosomal count for a species
numerical mutations
91
It affects the number, not the physical structure (of a species).
numerical mutations
92
The primary cause of numerical mutations is
nondisjunction
93
will lead to chromosomal imbalance that may
affect health and development of an individual.
numerical mutations
94
two types of numerical mutations
aneuploidy
polyploidy
95
The change in the number of an
individual chromosome within
a set
aneuploidy
96
(2n - 1)
monosomy
97
(2n + 1)
trisomy
98
(2n - 2)
nullisomy
99
(2n + 2)
tetrasomy
100
The change in the number in
the entire sets of the
chromosome.
polyploidy
101
example of polyploidy
triploidy
tetraploidy
102
(3n)
triploidy
103
(4n)
tetraploidy
104
The error in chromosomal segregation during cell division.
This occurs when homologous chromosomes or sister chromatids fail to
move properly from opposite poles.
nondisjunction
105
nondisjunction happens during
anaphase of meiosis I and II, and mitosis
106
down syndrome
trisomy 21
107
monosomy X
turner syndrome
108
XXY
klinefelter syndrome
109
trisomy 18
edwards syndrome
110
trisomy 13
patau syndrom
111
is a hallmark for cancer.
aneuploidy
112
detection methods for chromosome mutation
microscopic analysis
advance molecular techniques
113
microscopic analysis for mutation detection is
karyotyping
FISH
microarray analysis
114
Advanced Molecular
Techniques for mutation detecting
PCR-based method
electrophoretic method
protein truncation test (PTT)
115
key uses to detect Aneuploidy, large
translocations
karyotyping
116
technology used to detect microdeletions, gene fusions
karyotyping
117
key used for genome wide CNV screening
microarray
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key use cases for rare mutation quantification
dPCR
119
key use for SNP screening, methylation analysis
high resolution melting
120
technology used for clinical settings
karyotyping
FISH
121
technology used for microdeletion analysis
PCR and microarrays
122
technoogy used for research
dPCR and NGS
123
Deletion of the short
arm of chromosome
cri-du-chat syndrome
124
A cry that is high-pitched and cat-like
Low birth weight and slow growth
Intellectual disability and delayed development
Distinct facial features
cri-du-chat
125
Distinctive facial features
Heart defects
Bleeding disorder called Paris-Trousseau syndrome
Short stature
Frequent sinus and ear infections
Abnormalities of their digestive system, kidneys, and genitalia
Jacobsen Syndrome
126
Deletion of genetic
material from
chromosome 11.
Jacobsen syndrome
127
Also known as 22q11.2 deletion syndrome
A small part of chromosome 22 is missing
1 in 10 cases (10%), the 22q11 deletion is passed on to
a child by a parent who has this snydrome
digeorde syndrome
128
learning and behavior problems
speech and hearing problems – "nasal-sounding"
voice
mouth and feeding problems – a gap in the top
of the mouth or lip cleft lip or palate
heart problems
hormone problems
digeorge syndrome
129
change in DNA sequence of a gene
gene mutation
130
acts as instructions for body’s development and
function
DNA
131
are a key source of genetic diversity and evolution
mutation
132
is a
change in the DNA sequence
where a single nucleotide is
altered.
missense mutation
133
= single base change ➔ wrong amino acid ➔ possible change
in protein function.
missense mutation
134
example of gene mutation (Deletion)
cystic fibrosis
duchenne muscular dystrophy
135
also known as
point mutations, are those
mutations that affect a single
base pair.
substitutions
136
are changes in DNA that affect genetic
information.
gene mutation
137
gene mutatio ncan be __ or __
spontaneous
induced
138
type of gene mutation
substitution
insertion
deletion
139
(eggs and sperm) can
be passed on to offspring,
germline mutations
140
mutations in body cells
somatic mutations
141
WHY STUDYING MUTATION
MATTERS?
Source of genetic variation
Key to personalized medicine (e.g. genetic
testing identifies disease-related
mutations for early diagnosis and
preventive care).
Provides insights into gene function,
regulation, and interaction, enabling
innovations in gene therapy, diagnostics,
and biotechnology.
Utilized in agriculture for genetically
modified crops.
142
Point mutation converting a coding codon
into a STOP codon (UAA, UAG, UGA)
nonsense mutation
143
It introduces an early stop codon
(nonsense codon) in the mRNA
sequence.
nonsense mutation
144
Can have a dominant-negative
effect by interfering with regular
cellular functions.
nonsense mutation
145
nonsense mutation example
duchenne muscular dystrophy
146
nonsense mutation in ___ changes the color of their skin from white to brown
frog
147
is a change in a single
nucleotide that results in the substitution of
one amino acid for another in the resulting
protein.
missense mutation
148
occurs when an amino acid with similar properties is added
conservation missense mutation
149
is a type of missense mutation where the alteration in nucleotide causes the formation of a completely different kind of amino acid in the chai
non conservative
150
Changes in DNA that happen without
exposure to external agents (like
radiation or chemicals).
spontaneous mutation
151
Result from normal cell activities, such
as DNA replication or base changes.
Occur at a low but constant rate.
Part of natural genetic variation across all
life.
spontaneous mutation
152
Bases like T and C can temporarily
switch forms
tautomeric shifts
153
Leads to incorrect base pairing
during replication
ex: thymine pairs with guanine
tautomeric shifts
154
Loss of an amino group from a
base
Cytosine → Uracil → pairs with A
Changes G≡C to A=T if not
repaired
deamination
155
Loss of purine base (A or G),
leaving a gap
Polymerase may insert a
random base
Happens thousands of times
daily (Lindahl, 1993)
depurination
156
example of spontaneous mutation
tay-sachs
cystic fibrosis
duchenne MD
157
Alterations in the DNA
sequence caused by external agents called
mutagens.
induced mutation
158
Occur due to intentional or environmental
influences, unlike spontaneous mutations
which arise from natural cellular errors
induced mutation
159
small changes
(e.g., point mutations)
micromutation
160
large-scale
changes (e.g., deletions, translocations)
macro mutations
161
main categories of mutagens
physical
chemical
162
physical mutagens include
ionizing radiation
non ionizing radiation
163
X-rays, gamma rays
Causes DNA strand
breaks & large
mutations
ionizing radiation
164
UV light
Forms thymine dimers
→ disrupts replication
non ionizing radiation
165
chemical mutagens
base analogs
alkylating agents
intercalating agents
deaminating agents
166
E.g., 5-Bromouracil →
mispairing during replication
base analogs
167
Add alkyl groups →
mispairing, strand breaks
alkylating agents
168
Insert into DNA → frameshift
mutations
intercalating agents
169
E.g., Nitrous acid → base
conversion (C → U)
deaminating agents
170
Mutations with invisiblephenotypic changes.
ex: SubstitutionInsertionDeletion
micromutations
171
Guanine oxidized to 8-oxoguanine, which mispairs withadenine, leading to G-C → T-Atransversions.
what kind of induced mutation
micro mutation
172
uses repair mechanisms like excision
repair and photoreactivation. for UV induced mutation
E.coli
173
Mutation with distinct
morphological changes in the
phenotype
macromutation
174
A CASE OF INDUCED MUTATION IN WHEAT
sharbati sonora
175
Origin: Developed from Mexicanwheat variety 'Sonora 64'
Method: Gamma irradiation inducedmutation
Developed by: Dr. M.S.Swaminathan and team
Traits: High yield, amber-coloredgrains, improved protein content
Significance: Contributed to India'sGreen Revolution
sharbati sonora
