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Chapter 19 Flashcards

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1
Q

A heritable change in the genetic material is called a _______.

A

mutation

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2
Q

A _____ mutation refers to a mutation in which just one base is changed within the DNA sequence.

A

Point

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3
Q

A silent mutation is a mutation that results in ______.

A

No change to the amino acid sequence of the polypeptide

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4
Q

A base substitution in DNA that ultimately leads to a change in the encoded amino acid is called a(n) ____ mutation.

A

missense

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5
Q

What type of mutation involves a change from a normal codon to a stop codon?

A

nonsense mutation

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6
Q

A change in a single base pair in the genetic material is known as a ______ mutation.

A

Point

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7
Q

What can cause a frameshift mutation?

A

A nucleotide addition or deletion

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8
Q

Mutations that occur in a promoter sequence can be divided into two types: ______ promoter mutations increase the transcription rate, while ______ promoter mutations decrease it.

A

Up
Down

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9
Q

A mutant Drosophila fly can land on the side of a fly bottle when the bottle is incubated at 20-23 degrees but not at 24-27 degrees. This is an example of a _______ mutation.

A

Conditional

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10
Q

A suppressor mutation is so named because it suppresses the ______.

A

phenotypic effect of another mutation

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11
Q

The region where two chromosome pieces break apart and reattach to other chromosome pieces is called a chromosomal _____.

A

breakpoint

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12
Q

What is replica plating?

A

A technique in which a replica of bacterial colonies is transferred to a new petri plate using a velvet cloth

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13
Q

That mutations can occur in any gene and do not involve exposure of an organism to a particular condition that causes specific types of mutations to happen is consistent with the ______ theory.

A

Random mutation

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14
Q

A suppressor mutation is so named because it suppresses the ______.

A

Phenotypic effect of another mutation

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15
Q

Errors in DNA replication are examples of ______ mutations, while mutations caused by ultraviolet light are ______ mutations.

A

Spontaneous
Induced

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16
Q

Mutations that remove an adenine or guanine from the DNA are known as ______.

A

depurination

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17
Q

If an individual possesses a germ-line mutation, then ______ of the gametes produced by the individual will carry the mutation. If an individual possesses a somatic mutation, then ______ of the gametes produced by the individual will carry the mutation.

A

Half
None

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18
Q

Apurinic site

A

A site in DNA that is missing a purine base

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19
Q

Deamination

A

The removal of an amino group from a molecule (figure shown with cytosine)

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20
Q

Mutations can be caused in two main ways: (1) _______ mutations are the result of natural biological or chemical processes; and (2) ________ mutations are produced by environmental agents.

A

Spontaneous
Induced

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21
Q

A tautomeric shift is a ________.

A

temporary change in base structure

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22
Q

A mutation that involves the removal of a purine from DNA is called _______.

A

Depurination

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23
Q

Which of the following are forms of tautomers?

A

enol
amino
keto
imino

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24
Q

An individual that has somatic regions that are genotypically different from each other.

A

Genetic mosaic

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25
For a tautomeric shift to cause a mutation, it must occur ______.
Immediately prior to DNA replication
26
The removal of an amino group from a base is called _______.
Deamination
27
Products of oxygen metabolism, such as hydrogen peroxide, superoxide, and hydroxyl radical, are collectively called _______ ________ species.
Reactive Oxygen
28
The base cytosine is deaminated to produce the base _____.
Uracil
29
Which of these are used by cells to limit the harmful effects of reactive oxygen species?
Catalase Vitamin C (antioxidants) superoxide dismutase
30
A temporary change in base structure due to movement of hydrogen atoms is called a(n) _______ ________.
Tautomeric shift
31
An imbalance between the production of reactive oxygen species and an organism's ability to break them down is known as _______ _______.
Oxidative stress
32
Bases which exist in keto and enol or amino and imino forms are best described as ______.
Tautomers
33
Assume a tautomeric shift occurred for a thymine base, and was followed by two rounds of DNA replication. If the mutation is not repaired, the result would be a(n) ______ to ______ mutation in ______ of the four daughter molecules.
AT; GC One
34
Reactive oxygen species (ROS) are Blank______.
Products of oxygen metabolism in all aerobic organisms
35
Oxidative DNA damage refers to changes in DNA structure that are caused by ______.
reactive oxygen species
36
Trinucleotide repeat expansions are repeated sequences of three bases which ______.
increase in number from generation to generation
37
Which of these are disorders that involve trinucleotide repeat expansion?
Huntington Disease Fragile X syndromes myotonic muscular dystrophy
38
Proteins associated with trinucleotide repeat expansion disorders typically contain long tracts of the amino acid ________.
Glutamine
39
Genetic anticipation refers to which phenomenon?
an increase in severity of the symptoms as a disease that is passed through future generations
40
Place the steps in the process of expanding a trinucleotide repeat in order, with the first step at the top.
1. Dna replication proceeds past the region with trinucleotide repeats 2. A hairpin involving CG base pairing forms in the daughter strand 3. DNA polymerase temporarily slips off the template. 4. DNA polymerase backs up and continues DNA synthesis from the end of the hairpin 5. The hairpin spreads out, leaving a gap in the opposite strand 6. DNA polymerase and ligase repair the gap
41
The phenomenon in which a repeated sequence of three bases increases in number generation after generation is called
trinucleotide repeat expansion
42
A mutagen is a(n) ______.
agent that causes mutations
43
In trinucleotide repeat expansion disorders, when the expansion occurs in the coding sequence of the gene, the repeat sequence is usually ______.
CAG
44
Physical mutagens include ______.
both Xray and UV light
45
The formation of a hairpin during DNA replication can lead to an increase in the length of a DNA region if it occurs in ______.
the newly made daughter strand
46
Nitrous acid changed the base adenine to hypoxanthine, which pairs with the base _____. This leads to mutations in the newly-synthesized DNA strand during DNA replication.
Cytosine
47
Alkylating agents covalently attach ______ or ____ groups to DNA bases, and thus disrupt their normal base pairing properties
methyl or ethyl
48
Intercalating agents like acridine dyes induce mutations by ______.
inserting themselves between adjacent bases and thus distorting DNA structure
49
Proflavin is best described as a(n) ______ agent.
Intercalating
50
Certain compounds have a structure similar to normal DNA bases and so can be incorporated into daughter strands during DNA replication. These compounds are called base
analog
51
Acridine dyes cause ______ mutations
frameshift
52
What are the base analogs?
5-bromouracil 2-aminopurine
53
The formation of a hairpin during DNA replication can lead to an increase in the length of a DNA region if it occurs in ______.
the newly made daughter strand
54
Gamma rays and c-rays are examples of a type of radiation called _________ radiation.
Ionizing
55
Acridine dyes are planar molecules that include ______.
proflavin
56
Base analogs induce mutations by ______.
substituting for normal bases during DNA replication
57
How does ionizing radiation cause mutations?
It forms free radicals that can introduce breaks into the DNA molecule
58
What is true about nonionizing radiation?
Includes ultraviolet light has low energy
59
Thymine dimers are typically caused by ______.
ultraviolet light
60
Proflavin is best described as a(n) ______ agent.
intercalating
61
The mutation rate is commonly expressed as the number of new mutations ______.
in a given gene per cell generation
62
The Ames test assays whether an agent causes ______.
gene mutations
63
The bacterium used in the Ames test is ______.
Salmonella typhimurium
64
Ultraviolet light causes the formation of crosslinked _______ ______ in DNA.
Thymine dimers
65
The process by which thymine dimers are directly repaired with the help of light is called _____.
photoreactivation
66
The Ames test uses a strain of the bacterium Salmonella typhimurium that is unable to produce the amino acid ______.
histidine
67
The proteins UvrA, UvrB, UvrC, and UvrD are required for the DNA repair system called ______ repair.
nucleotide excision
68
Which of these represents the correct order of steps during a typical DNA repair system?
Detection>removal>replication
69
The following are steps in the nucleotide excision repair (NER) system. Place them in order, starting with the earliest on top
1. UvrA/UvrB complex tracks along the DNA in search of damaged DNA 2. UvrA is released and UvrC binds 3. UvrC makes cuts on both sides of the thymine dimer 4. UvrD removes the damaged region 5. UvrB and UvrC are released 6. DNA polymerase fills the gap and DNA ligase seals the region.
70
Photoreactivation is a repair mechanism that can Blank______ a thymine dimer in the Blank______ of light.
Directly split presence
71
Nucleotide excision repair (NER) is the main system used in the repair of ______.
bulky, helix distorting lesions
72
Nucleotide excision repair (NER) is found in ______.
both prokaryotes and eukaryotes
73
In the nucleotide excision repair (NER) system, the damaged DNA is recognized by the ______, and removed by the action of the proteins ______.
UvrA/UvrB complex UvrC (endonuclease) and UvrD (helicase)
74
In the mismatch repair system, how is the newly made daughter strand distinguished from the parental strand?
The parental strand is methylated while the daughter strand is not
75
In the mismatch repair system, the proteins ______ form a complex that activates ______, which is already bound to a ______ DNA site.
MutS/MutL MutH Hemimethylated
76
What can cause double-strand breaks (DSBs)?
Gamma rays Reactive oxygen species X-rays
77
During the normal course of DNA replication, the addition of a nucleotide that does not obey the AT/GC rule of base pairing creates a ______.
base pair mismatch
78
Double-strand breaks are typically repaired by?
nonhomologous end joining homologous recombination repair
79
f the proofreading ability of a DNA polymerase fails, which of the following DNA repair systems is most likely to detect the resulting mutations and fix them?
mismatch repair system
80
The strand that is repaired in the mismatch repair system is ______.
the nonmethylated strand
81
Translesion synthesis refers to the ______.
replication of a template strand that contains DNA damage
82
What is the role of MutS?
detects the mismatch
83
What is the role of MutL?
Acts as a linker that helps loop the DNA
84
What is the role of MutH?
makes a cut in a nonmethylated strand
85
What is the role of MutU?
separates strands at the cleavage site
86
What is the role of exonuclease?
digests the nonmethylated strand
87
The breakage of chromosomes is referred to as a ______-_____ break.
Double-strand
88
The synthesis of DNA over a template strand that harbors some type of DNA damage is called______ synthesis.
translesion
89
Thymine dimers weaken _______.
Hydrogen bonds
90
What protein cuts the damaged DNA strand?
UvrC
91
which protein has a helicase function?
UvrD
92
What synthsizes the new DNA strand?
DNA polymerase
93

Genetics (8 decks)

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