UNIT 6: GENETIC MUTATIONS Flashcards
1
Q
alteration in the chromosome structure or chromosome number
A
Chromosomal mutation
2
Q
<1% of population
A
Mutation
3
Q
> 1% of population
A
Polymorphism
4
Q
A wobble has a maximum of ___ permissible changes.
A
1/3
5
Q
At least two alternate DNA sequences; generally not assoc. with diseases
A
Genetic polymorphism
6
Q
any heritable change in the amount or structure of genetic material
A
Genetic mutation
7
Q
Classification of mutations can be based on
A
Origin
Cell type
Expression
Effect on function
Molecular change and its e ffects on protein products
8
Q
Choice of testing for genetic mutations
A
Probing using molecular tests like FISH and CGH
9
Q
Test for chromosomal mutation
A
Karyotyping
10
Q
For polymorphism, single base pair change in the nucleotide sequence is called a
A
Single nucleotide polymorphism
11
Q
For mutation, single base pair change in the nucleotide sequence is called a
A
Point mutation
12
Q
the DNA polymerase’s ability to correct changes in the DNA
A
Fidelity
13
Q
rapidly dividing cells are more prone to have a mutation due to
A
Adaptability
14
Q
Based on Origin
A
Spontaneous / Induced
15
Q
Occurs in the absence of known mutagen
Statistically random, unpredictable events
A
Spontaneous
16
Q
Occurs in presence of known mutagen
Usage of offending agent
A
Induced
17
Q
Mutagens based on effect
A
Teratogens
Carcinogens
Clastogens
Non-specific
18
Q
an agent that changes genetic material
A
Mutagen
19
Q
Teratogens result in
A
Congenital malformation
20
Q
Rapid, uncontrollable proliferation of cells
A
Cancer
21
Q
There is a limitation on how we can control mutation and its e ffect on environmental or population genetics.
A
Drift-barrier hypothesis
22
Q
Teratogens affect the overall structure because they target __________ stem cells
A
pluripotent
23
Q
Carcinogens result in
A
Tumor formation
Cancer
24
Q
Clastogens result in
A
Chromosomal abnormalities
25
Nonspecific mutagens result in
DNA Damage
26
3 Classifications of Mutagens
Physical
Chemical
Biological
27
Physical mutagens
I Hate Nothing
- Ionizing radiation
- Heat
- Non-ionizing radiation
28
are like bullets; cause double stranded breaks
ex. X-rays, Cosmic rays, Gamma rays
Ionizing radiations
29
high-energy enough to cause thymine dimerization
ex. UV rays
Non-ionizing radiations
30
Part of atomic decay
ex. Alpha particle, Beta particle, Fast neutron, Thermal neutron
Heat
31
Chemical mutagens
ADI agents
- Alkylating agents
- Deaminating agents
- Intercalating agents
32
Stain that can cause cancer
would get inside the double stranded DNA
Ethidium Bromide (EtBr)
33
Biological Mutagens
BB agents
- Biological agents
- Biological infectious agents
34
Examples of Biological agents
Virus
Bacteria
Transposons
35
Natural elements of DNA that jump
Transposons
36
In cases of sunburn, what is removed from the DNA by the corrective mechanism of the body?
Thymine dimer
37
Most energetic type of UV light
UV C
38
Hydrocarbon involved in smoking
Polycyclic Aromatic Hydrocarbons (PAH)
39
Hydrocarbons involved in smoking
Polycyclic Aromatic Hydrocarbons (PAH)
40
In smoking, bulky DNA adducts at _______
guanines
41
Hydrogen peroxide is reversed by
Vitamins
42
Hydrogen peroxide is reversed by
Vitamins
43
mostly harmful to the body but useful in neutrophils
Oxygen free radicals
44
Transformation of structure
ex. C to 5mC
Tautomerization
45
corrects dipyrimidine photoproducts in some organisms
not present in humans
Photolyases
46
mimics the bases
similar but not exactly the same
Base analogs
47
chemotherapy medication used to treat various types of cancer, including leukemia, lymphoma, neuroblastoma, and Wilms tumor
Vincristine
48
chemotherapy medication, typically used with other medications, to treat a number of types of cancer including Hodgkin's lymphoma, non-small-cell lung cancer, bladder cancer, brain cancer, melanoma, and testicular cancer
Vinblastine
49
Based on Cell type
Somatic and Germ line
50
Occurs in nonreproductive cells
Can yield a genotypic mixture (mosaic) of normal and mutant tissue
Most common cancers
Somatic
51
Occurs in reproductive cells
Inherited
Can be de novo from the parent passed to the offspring
Germ line
52
Sperms are associated with germ line mutations because
they are more prone to errors in mutation
53
paternal : genetic mutation
maternal: ___________
aneuploidy
54
Examples of Germ line mutation
Sickle cell anemia, cystic fibrosis, and color blindness
55
Based on Expression
Conditional
Unconditional
56
Expressed only under restrictive conditions (ex. high temperature)
Effect of mutation can be turned on or off by experimenter
Conditional
57
Expressed under permissive conditions as well as restrictive condition
Expressed all the time with no preconditions
Unconditional
58
Based on Effect on Function
Loss of function (amorphic and hypomorphic)
Gain of function (hypermorphic, neomorph, antimorphic)
59
Based on Effect on Function
Loss (amorphic and hypomorphic) and Gain (hypermorphic, neomorphic, and antimorphic)
60
other name for amorphic mutation
knockout or null mutation
61
Eliminates normal function
Results in complete gene inactivation or in a completely nonfunctional gene product
Amorphic
62
other name for Hypomorphic mutation
leaky mutation
63
Reduces normal function, but does not eliminate, the level of expression of a gene or the activity of the gene product
Hypomorphic
64
Individuals with hypomorphic mutations may have enough enzyme activity to “leak through” to produce a _____________ phenotype
quasi-normal
65
Increases normal function
Produces a greater-than-normal level of gene expression (mutation changes the regulation of the gene so that the gene product is overproduced)
Hypermorphic
66
other name for neomorph
ectopic expression
67
other name for neomorph
ectopic expression
68
Expressed at incorrect time or in inappropriate cell types (new function)
Qualitatively alters the action of a gene
Neomorph
69
Mutant gene product interferes with normal gene product
Antimorphic
70
Based on Molecular Change
Substitutions
Deletions
Insertions
Duplications
Inversions
Translocations
71
In molecular genetics, base-pair substitutions are also termed _______ ____________
point mutations
72
In classical genetics, point mutations denote any mutation that are
small enough to be unobservable under a microscope
73
temporarily stop or decrease the expression of one or more targeted genes
Gene knockdown
74
Most common type of mutation
Substitution
75
Replacement by the same type of nucleotide
ex. C for T; A for G
Transition Substitution
76
Substitution of a pyrimidine by a purine or vice versa
ex. A for T; C for G
Transversion Substitution
77
Defense mechanism in substitution
Degeneracy
78
the ability of elements that are structurally different to perform the same function or yield the same output
Degeneracy
79
the regions in the DNA sequence, which comprises cytosine followed by guanine from 5′ to 3′ direction
CpG sites
80
most common type of point mutation
Transition substitution
81
Involves the loss of one or more nucleotides
Deletion
82
Deletion of amino acids that may affect protein function or stability
Multiple of 3 nucleotides (codon)
83
Deletion pattern that likely results in frameshift mutation
Not multiple of 3
84
Deletion of amino acids that may affect protein function or stability
Multiple of 3 (codon)
85
Deletion that may arise through unequal crossover between repeat sequences
Either: Partial gene deletion or Whole gene deletion
Large deletion
86
Three-base deletion in the common cystic fibrosis (CF) allele results in synthesis of a protein that lacks:
amino acid 508 (phenylalanine)
87
Involves the addition of one or more nucleotides into a gene
Insertion
88
Insertion of amino acids that may affect protein function or stability
Multiple of 3 nucleotides (codon)
89
Insertion pattern that likely results to frameshift mutation
Not multiple of 3
90
Results from unequal crossover (e.g., hereditary sensory and motor neuropathy
type 1a) or the insertion of transposable elements
Large insertion
91
examples of Expansion of trinucleotide repeat
Huntington disease
Triple X syndrome
Myotonic dystrophy
Friedreich ataxia
92
Amplification of a sequence of three nucleotides, which prevents normal expression of the gene
Involves dynamic mutations wherein the repeat sequence becomes more unstable as it expands in size
Expansion of trinucleotide repeat
93
Expansion of trinucleotide repeat mostly contains bases __ and/or __
C ; G
94
Based on Effect on Protein Products
Synonymous (silent) and Nonsynonymous (missense, nonsense, and frameshift)
95
Mutation does not alter the polypeptide product of the gene
Synonymous
96
Mutation leads to an alteration in the encoded polypeptide
Likely to result in abnormal function, which is usually associated with disease, or lethality
Nonsynonymous
97
Base-pair substitutions that produce a change in a single amino acid
Missense
98
substitution involving different groups of amino acids
nonconservative missense mutation
99
substitution involving same groups of amino acids
conservative missense mutation
100
Sickle cell anemia affects the _________ ______ of hemoglobin
β-globin chain
101
Amino acids involved in sickle cell anemia
Glutamic acid (normal) to Valine (mutant) at the 6th position out of 147 AA
102
Base-pair substitutions that produce a stop codon in the mRNA
Result in a premature termination of the polypeptide chain
Unlikely to retain normal biological activity, especially when there is a loss of an important functional domain(s) of the protein
Nonsense
103
Nonsense mutation wherein the codon for glutamine (CAG) creates a stop codon (UAG) as U, substituted for C
β0-thalassemia
104
When a mutation involves the insertion or deletion of nucleotides that are not a multiple of three
Resulting amino acid sequence bears no resemblance to the normal sequence and may have an adverse effect on its function
Frameshift
105
Other term for Frameshift mutation
indel
106
Frameshift mutation that involves a four-base (TATC) insertion in the hexosaminidase A gene
Tay-Sachs disease
107
mutation that happens in areas where exons must be cut and stick together
Splice Site Mutation
108
Types of Splice Site Mutation
Exon skipping, Intron inclusion, Cryptic
109
Consequence of Frameshift mutation
From mutation to end of the sequence is incorrect
