Chapter 19

Select all that apply What can cause double-strand breaks (DSBs)? -X-rays -Gamma rays -Reactive oxygen species -Ultraviolet light

-X-rays -Gamma rays -Reactive oxygen species

A germ-line mutation is one that occurs in ______. -a sperm or egg cell -any cell after zygote formation -any body cell other than gametes -a virus or a bacterial cell

-a sperm or egg cell

The probability that a gene will be altered by a new mutation is referred to as the ____ ____.

mutation rate

The mutation rate is commonly expressed as the number of new mutations in a given ______. -chromosome per cell generation -gene per cell generation -genome per population -gene per genome size

-gene per cell generation

Select all that apply Which changes can cause a frameshift mutation? A base addition A base transition A base deletion A base transversion

A base deletion A base addition

A mutation that enhances the survival and/or reproductive success of an individual is referred to as a(n) ____.

Beneficial mutation

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.

Blank 1: spontaneous Blank 2: induced

True or false: Deleterious mutations that cause the death of a cell are called nonsense mutations.

False

The process by which thymine dimers are directly repaired with the help of light is called ____

Photoreactivation

True or false: Most DNA repair systems involve three major steps: detection of the error, removal of the abnormality, and its replacement with normal DNA.

True

The addition or deletion of a number of bases that is not a multiple of 3 causes a(n) ____.

frameshift mutation

Base excision repair (BER) is the main system used in the repair of ______. -mismatched bases -double-strand breaks -abnormal bases -single-strand breaks

-abnormal bases

A mutant allele is best defined as an allele that ______. -encodes a protein that causes a disease -has a different DNA sequence from the wild-type -can no longer be transcribed into mRNA

-has a different DNA sequence from the wild-type

The process by which chromosomes exchange similar or identical DNA segments during meiosis is called ______. -site-specific recombination -non-homologous recombination -transposition -heterologous recombination -homologous recombination

-homologous recombination

Trinucleotide repeat expansions are repeated sequences of three nucleotide bases which ______. -increase generation after generation -are associated with various cancers -increase in number via reciprocal translocations -are used as templates to repair damaged DNA

-increase generation after generation

Oxidative DNA damage refers to changes in DNA structure that are caused by ______. -alkylating agents -non-ionizing radiation -tautomeric shifts -reactive oxygen species

-reactive oxygen species

A tautomeric shift is a ______. -base change caused by ultraviolet light -temporary change in gene expression -temporary change in base structure -base change caused by chemical agents

-temporary change in base structure

Changes to DNA structure caused by reactive oxygen species (ROS) are termed ____ ____ ____.

Oxidative DNA damage

Mutations that remove an adenine or guanine from the DNA are known as ______. -depurinations -deaminations -decarboxylations -depyrimidinations

-depurinations

Photoreactivation is a repair mechanism that can ______ a thymine dimer in the ______ of light. -induce; presence -directly split; absence -directly split; presence -excise; absence

-directly split; presence

Errors in DNA replication are examples of ______ mutations, while mutations caused by ultraviolet light are ______ mutations. -frameshift; point -spontaneous ; induced -induced ; spontaneous -point ; frameshift

-spontaneous ; induced

A deleterious mutation is best defined as one that decreases the chance of ______. -survival and reproduction -DNA replication -mRNA transcription -normal chromosome segregation

-survival and reproduction

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

Blank 1: up Blank 2: down

The phenomenon in which a repeated sequence of three nucleotide bases increases in number generation after generation is called _______.

Trinucleotide repeat expansion

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

missense mutation

An agent that can change DNA structure and cause mutations is known as a(n) ____.

mutagens

A(n) ______ mutation refers to a mutation in which just one base is changed within the DNA sequence. point locus core allele

point

A change in a single base pair in the genetic material is known as a(n) ____.

point mutation

Mutations in body cells that do not go on to form gametes are known as ______ mutations. somatic conditional germ-line auxotrophic

somatic

A change of one base for another is described as a base ____ mutation.

substitution or point

Select all that apply Which of the following are examples of base pair mismatches? -Cytosine on parent strand and Thymine on daughter strand -Cytosine on parent strand and Adenine on daughter strand -Adenine on parent strand and Thymine on daughter strand -Cytosine on parent strand and Guanine on daughter strand -Adenine on parent strand and Cytosine on daughter strand

-Cytosine on parent strand and Thymine on daughter strand -Cytosine on parent strand and Adenine on daughter strand -Adenine on parent strand and Cytosine on daughter strand

Select all that apply Which of the following statements about promoter mutations is true? -Down promoter mutations occur in the 3'-UTR of the gene -Up promoter mutations cause the promoter sequence to be more like the consensus sequence -Up promoter mutations occur in the coding sequence of the gene -Down promoter mutations decrease the affinity of transcription factors to the promoter

-Up promoter mutations cause the promoter sequence to be more like the consensus sequence -Down promoter mutations decrease the affinity of transcription factors to the promoter

Homologous recombination is a process in which -small segments of DNA can move to multiple locations within the chromosomal DNA. -the DNA of viral genomes is integrated into host cell DNA. -a portion of one chromosome is transferred to a new location on a non-homologous chromosome. -a new combination of DNA sequences is formed through breakage and rejoining of similar or identical DNA segments.

-a new combination of DNA sequences is formed through breakage and rejoining of similar or identical DNA segments.

A mutagen is a(n) ______. -agent that causes mutations -organism that has undergone a mutation -protein that repairs mutated DNA

-agent that causes mutations

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 tautomer -frameshift mutation -base pair mismatch -dynamic mutation

-base pair mismatch

Nucleotide excision repair (NER) is the main system used in the repair of ______. -bulky, helix distorting lesions -abnormal bases -small, helix non-distorting lesions -mismatched bases

-bulky, helix distorting lesions

The term germ line is used to describe the ______. -area where chromosomes line up during cell division -region where cells form the cleavage furrow during mitosis -cells that produce sperm and eggs -cells that defend again microbes

-cells that produce sperm and eggs

Select all that apply Which are examples of somatic mutations? -A mutation in an embryonic kidney cell -A mutation in a sperm cell -A mutation in an egg cell -A mutation in an adult muscle cell

-A mutation in an embryonic kidney cell -A mutation in an adult muscle cell

Select all that apply Which of these point mutations would likely have an inhibitory effect on protein function? Missense Silent Frameshift Nonsense

Missense Frameshift Nonsense

The removal of a purine from DNA is called ____.

depurination or depurinization

Some errors affect individual nucleotides and do not distort the DNA double helix. These errors are removed primarily by a DNA repair system called BER, which stands for ____ ____ ____.

base excision repair

The breakage of chromosomes is referred to as a(n) ___-___ break.

double strand

Cells that give rise to the gametes such as eggs and sperm are called ____.

germ line or germ cells

A temporary change in base structure due to movement of hydrogen atoms is called a(n) ______.

tautomeric shift

A mutation that occurs directly in a sperm or egg cell, or in one of their precursor cells, is referred to as a(n) _____.

germ-line mutation

The wild type genotype or phenotype is the one that is ______ found in nature. typically rarely always never

typically

In a natural population, a _____ genotype is the most common one.

wild type

Which of these represents the correct order of steps during a typical DNA repair system? Detection → Removal → Replication Replication → Removal → Detection Replication → Detection → Removal Detection → Replication → Removal

Detection → Removal → Replication

A mutation that results in the death of an organism is known as a(n) ____.

lethal mutation

A mutation in a gene that causes an amino acid change in the encoded protein is called a ______ mutation. missense silent sense nonsense

missense

An allele that has a DNA sequence different from that of the wild-type is called a(n) ____.

mutant

A heritable change in the genetic material is called a(n) ______. aberration mutation translesion transformation

mutation

The term ____ refers to an inherited change in the sequence of the genetic material.

mutation

Some errors create bulky distortions of the double helix. These errors are removed primarily by a DNA repair system called NER, which stands for ____ ____ ____.

nucleotide excision repair