MOD 5: DNA Mutation, Repair, and Transposons Flashcards
1
Q
What are the four characteristics of a genetic material?
A
- Replication
- Storage of information
- Expression of information
- Variation by mutation
2
Q
This refers to any change in an organism’s genome nucleotide
A
Mutation
3
Q
This refers to the source of genetic variation and provides the raw material for natural selection
A
Mutation
4
Q
Mutation leads to genetic damage and contributes to ____________, ____________, and ____________
A
Cell death; genetic diseases; cancer
5
Q
Mutation affects organisms depending on the type. What are the three known effects?
A
- Base-pair alteration
- Location of mutation
- Function of the affected gene product
6
Q
TRUE OR FALSE: Mutation can occur spontaneously
A
TRUE
7
Q
Natural biological mutation = ____________
Chemical processes = ____________
A
Happen naturally; external environment
8
Q
TRUE OR FALSE: Mutation can be induced by external factors
A
TRUE; By chemicals or radiation
9
Q
This type of mutation may cause a wide variety of human diseases
A
Single-gene mutations
10
Q
Mutations are counteracted by a number of ____________
A
DNA repair mechanisms
11
Q
This can cause chromosome breaks and induce mutations within coding and gene-regulatory regions
A
Transposable elements
12
Q
This reads the nucleotides in codons
A
tRNA
13
Q
What are the classifications of gene mutations?
A
- Point mutation
- Substitution
- Frameshift mutation
- Deletion
- Insertion
14
Q
This characteristic of the DNA allows the DNA to yield the same code even with changes on the last nucleotide
A
DNA wobble
15
Q
What are the three effects of function?
A
- Loss of function
- Gain of function
- Suppressor mutation
16
Q
This effect of gene mutation reduces or eliminates gene function — the gene is dead.
A
Loss of function
17
Q
This effect of gene mutation codes for gene products with enhances, negative, or new functions
A
Gain of function
18
Q
This effect of gene mutation is a second mutation that either reverts or relieves the effect of the previous mutation
A
Suppressor mutation
19
Q
What are the three types of mutation under the loss of function?
A
- Null mutation
- Recessive mutation
- Dominant mutation
20
Q
This refers to the complete loss of gene function in which two genes are affected
A
Null mutation
21
Q
This type of mutation shows wild-type phenotype — only one allele has the mutation; the other is still working.
A
Recessive mutation
22
Q
This type of mutation shows mutant phenotype.
A
Dominant mutation
23
Q
Dominant negative mutation may result from a disease in which one allele is inactivated.
Even though the other gene is still working, it won’t be expressed due to the small amount of gene products produced.
What do you call this disease?
A
Haploinsufficiency
24
Q
Mutation by Phenotypic Effects:
This classification of mutation shows visible morphological trait.
Example: Mendel’s pea characteristics
A
Visible
25
Mutation by Phenotypic Effects:
This classification of mutation alters nutritional characteristics.
Example: Loss of ability to synthesize an essential amino acid in bacteria
Nutritional
26
Mutation by Phenotypic Effects:
This classification of mutation yields changes in protein function.
Example: Defective hemoglobin leading to sickle-cell anemia in humans
Biochemical
27
Mutation by Phenotypic Effects:
This classification of mutation leads to behavior pattern changes.
Example: Brain mutations affecting Drosophila mating behaviors.
Behavioral
28
Mutation by Phenotypic Effects:
This classification of mutation yields altered gene expression.
Example: Regulatory gene mutations affecting expression of the lac operon in E. coli
Regulatory
29
Mutation by Phenotypic Effects:
This classification of mutation alters the organism’s survival.
Example: Tay-sachs and Huntington diseases in humans
Lethal
30
Mutation by Phenotypic Effects:
This classification of mutation occurs in which the phenotype expressed only certain environmental conditions.
Example: Temperature-sensitive mutations affecting coat color in Siamese cats
Conditional
31
What are the two types of location mutation?
1. Somatic mutation
2. Autosomal mutation
32
This type of location mutation occurs in any cell in the body except germ cells.
Somatic mutation
33
TRUE OR FALSE: Somatic mutation can be passed on across generations and affect offsprings.
FALSE; Gene remains with the person only.
34
This type of location mutation involves germ cells; x-linked and y-linked
Autosomal mutation
35
This type of location mutation involves germ cells; x-linked and y-linked
Autosomal mutation
36
TRUE OR FALSE: Autosomal mutation can be passed on to offspring
TRUE
37
This type of mutation can occur spontaneously through natural biological and/or chemical processes.
Spontaneous mutations
38
What is the difference between germ line cells and not germ line cells?
In germ line cells, the whole body gets the mutation
In not germ line cells, only patches in the tissue of the mutation are affected
39
This type of mutation can be induced by external factors such as chemicals and/or radiation.
Induced mutations
40
This refers to the likelihood that a gene will undergo mutation in a single generation
Mutation rate
41
TRUE OR FALSE: Mutation rate varies between organisms but is the same within the species.
FALSE; Mutation rate also varies within the species, from gene to gene.
42
This refers to the part of the gene that is usually mutated
Mutation hot spots
43
In slippage, when looping occurs on the newly synthesized strand, what happens to the nucleotides?
The result is the addition of nucleotides
44
In slippage, when looping occurs on the template strand, what happens to the nucleotides?
The result is the omission of nucleotides
45
This refers to the transfer of double bonds
Tautomeric shifts
46
Tautomeric shifts are caused by the movement of __________
Protons
47
This refers to the loss of one of the nitrogenous bases in an intact double-helical DNA molecule
Depurination
48
What are the two usual nitrogenous bases involved in depurination?
Guanine and adenine
49
What two nitrogenous bases are involved in deamination?
Cytosine and adenine
50
In deamination, an amino group in cytosine or adenine is converted into a __________ group
Keto
51
In these bases, cytosine is converted to __________, and adenine is changed to __________ — resembling the compound, __________
Uracil; guanine; hypoxanthine
52
An oxygen that becomes more negative becomes a __________
Superoxide
53
TRUE OR FALSE: Superoxides are not really reactive
FALSE; They are highly reactive
54
Oxidative damage may cause 5 breaks. What are they?
1. Base mismatch
2. Single-strand breaks
3. Double-strand breaks
4. Crosslink inter-strand breaks
5. Crosslink intra-strand breaks
55
What are the four effects of oxidative damage?
1. Mitochondrial dysfunction
2. Synaptic deficit
3. Necrosis
4. Cognitive impairment
56
What are the causes of Reactive Oxygen Species (ROS)?
1. UV
2. Radiations
3. Chemical pollutants
57
What are the four chemical reactions under induced mutation?
1. Base analogs
2. Intercalating, alkylating, and adduct-forming agents
3. Ultraviolet light
4. Ionizing radiation
58
Base analogs show the similarity of the chemical structure of __________ and __________
5-bromouracil (5-BU) and thymine
59
In the common keto form, 5-BU base-pairs normally with __________
Adenine
60
In the rare enol form, 5-BU pairs anonymously with _________
Guanine
61
This refers to molecules that go in between DNA strands
Intercalating agents
62
What are the two dyes used as intercalating agents?
1. Acridine orange
2. Ethidium bromide
63
This refers to the dye that causes frameshift mutation by creating unusual spacing between nucleotides
Acridine orange
64
This refers to the dye that causes frameshift mutation by creating unusual spacing between nucleotides
Acridine orange
65
This refers to the dye that fluoresces when viewed under AGE
Ethidium bromide
66
Alkylating agents convert __________ to __________
Guanine to 6-ethylguanine
67
What alkylating agent converts guanine to 6-ethylguanine?
Ethylmethane sulfonate (EMS)
68
What nitrogenous base does 6-ethylguanine base-pair with?
Thymine
69
This mutating agent is effective, common, and does not always cause bad mutations.
Ethyl Methanesulfonate (EMS)
70
This is a segment of DNA bound to a cancer-causing chemical
DNA adduct
71
These are used as biomarkers of exposure in scientific experiments, binding to DNA and leading to cancer
DNA adduct
72
DNA adduct is usually a product of a reaction between __________ and __________
Chemicals and one’s DNA
73
This is a significant constituent of tobacco smoke
Acetaldehyde
74
This binds to DNA, causes crosslinking, and leads to cell death
Cisplatin
75
This is a naturally-occurring produce of lipid peroxidation
Malondialdehyde
76
What are the 14 chemicals that form DNA adducts?
1. Acetaldehyde
2. Cisplatin
2. DMBA
4. Malondialdehyde
5. Polycyclic Aromatic Hydrocarbons (PAHs)
6. Nitro-PAHs
7. Aflatoxins
8. Mustards
9. Aromatic Amines
10. Heterocyclic Aromatic Amines (HAAs)
11. Methylating Agents
12. Other alkylating agents
13. Haloalkanes
14. Nitrosamines
77
This refers to electromagentic spectrum and their associated wavelengths
Ultraviolet light and ionizing radiation
78
Mutations can be induced by many types of __________ and __________
Chemicals and radiation
79
What are the different types of mutation that causes disease?
1. Missense
2. Nonsense
3. Insertion
4. Deletion
5. Trinucleotide repeat expansions
80
This type of mutation causes the disorder achondroplasia.
Molecular change:
Glycine to arginine at position 380 of FGFR3 gene
Missense
81
This type of mutation causes the disorder Marfan syndrome.
Molecular change:
Tyrosine to STOP codon at position 2113 of fibrillin-1 gene
Nonsense
82
This type of mutation causes the disorder Familial hypercholesterolemia.
Molecular change:
Various short insertions through the LDLR gene
Insertion
83
This type of mutation causes the disorder cystic fibrosis.
Molecular change:
Three-base-pair deletion of phenylalanine codon at position 508 of CFTR gene
Deletion
84
This type of mutation causes the disorder Huntington disease
Molecular change:
>40 repeats of (CAG) sequence in coding region of Huntingtin gene
Trinucleotide repeat expansions
85
This is a hereditary condition in which the growth of long bones is restricted by the ossification of cartilage
Achondroplasia
86
This results in very short limbs and sometimes a face that is small in relation to the skull
Achondroplasia
87
The Marfan syndrome affects what tissue that provides support for the body and organs?
Connective tissue
88
This syndrome damages the blood vessels, heart, eyes, skin, lungs, and the bones of the hips, spine, feet, and rib cage
Marfan syndrome
89
Familial hypercholesterolemia is caused by a defect on what chromosome?
Chromosome 19
90
This disease makes the body unable to remove low density lipoprotein cholesterol from the blood
Familial hypercholesterolemia
91
What is damaged by cystic fibrosis?
The lungs, digestive tract, and other organs
92
This disease may be inherited and affect cells that produce mucus, sweat, and digestive juices
Cystic fibrosis
93
This consists of a group of human diseases that are a result of an abnormal expansion of repetitive sequences
Trinucleotide repeat disorders
94
What organ system is affected by the trinucleotide repeat disorders?
Nervous system
95
This DNA repair system detects incorrect bases and reverses them
Proofreading
96
This is activated when proofreading still has errors, replacing incorrect nucleotides with correct ones
Mismatch repair (MMR)
97
This repair system is the last resort type or repair, allowing cells to continue to survive even with a lot of damages/mutations
SOS Repair system
98
TRUE OR FALSE: The SOS repair system allows cells to survive without mutations
FALSE; Cells are enabled to survive, but are mutated
99
The SOS repair system is always repressed by what protein?
LexA protein
100
This revers to the reversal of UV damage, requiring UV-induced damage forming pyrimidine dimers
Photoreactivation repair
101
Photoreactivation repair is dependent on proteins called __________
Photoreactivation Enzyme (PRE) or phytolyase
102
TRUE OR FALSE: Photoreactivation repairs are present in humans but not in bacteria, fungi, plants, and some vertebrates
FALSE; Present in bacteria, fungi, plants and some vertebrates; Absent in humans
103
This is referred to as excision repair or cut-and-paste mechanisms
Base excision repair (BER)
104
What are the three steps in base excision repair (BER)?
1. Recognition of damage and enzymatically cliipping it out by an endonuclease
2. DNA polymerase fills in the gap
3. DNA ligase seals the final nick
105
What are the two types of base excision repairs (BER)?
Class 1 - Copy & Paste
Class 2 - Cut & Paste
106
This class of BER is the longer method, requiring the transposon to get transcribed, undergoing reverse transcription
Class 1 - Copy & Paste
107
This class of BER cuts the region and pastes it to another part. It is the shorter method
Class 2 - Cut & Paste
108
What are the two transposable elements in humans?
1. Long Interspersed Elements (LINEs)
2. Short Interspersed Elements ( SINEs)
