Assignment Chapter 19: Gene Mutation, DNA Repair, and Recombination

substitution

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

survival and reproduction

A deleterious mutation is best defined as one that decreases the chance of ______.

agent that causes mutations

A mutagen is a(n) ______.

missense

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

beneficial

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

nonsense

A mutation that results in premature termination of the synthesis of a polypeptide is called a(n)___________mutation.

change to the amino acid sequence of the polypeptide

A silent mutation is a mutation that results in no ______.

gene conversion

A situation in which one allele is changed to the allele found on the homologous chromosome is called ______.

mutagen

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

malaria

An individual that has one copy of the sickle cell allele and one copy of the wild-type allele has an increased level of resistance to the disease

homozygous

An individual that is ______ for the sickle cell allele has a decreased chance of survival.

hot spots

Areas within a single gene that are more likely to mutate than other regions are called____________ _________.

oxidative DNA damage

Changes to DNA structure caused by reactive oxygen species (ROS) are termed __________ ___________________ ____________.

more likely to mutate than other regions

Hot spots are regions of the chromosome that are ______.

splice

Mutations in eukaryotic genes that change the___________recognition sequences may affect the order and/or a number of exons contained in the mature mRNA.

The mRNA's ability to be translated The stability of the mRNA

Mutations in the 5'-UTR or 3'-UTR of an mRNA molecule are most likely to affect what?

bulky, helix distorting lesions

Nucleotide excision repair (NER) is the main system used in the repair of ______.

reactive oxygen species

Oxidative DNA damage refers to changes in DNA structure that are caused by ______.

directly split; presence

Photoreactivation is a repair mechanism that can ______ a thymine dimer in the ______ of light.

base excision

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_______ _________ repair.

nucleotide excision

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

frameshift

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

gene per cell generation

The mutation rate is commonly expressed as the number of new mutations in a given ______.

trinucleotide repeat expansion

The phenomenon in which a repeated sequence of three nucleotide bases increases in number generation after generation is called___________ ___________ __________.

mutation rate

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

breakpoint

The region where two chromosome pieces break and re-attach to other chromosome pieces is called a chromosomal_____________.

mutation

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

Base substitution

This figure best illustrates what type of mutation?

A germ-line mutation typically originates during meiosis whereas a somatic mutation typically originates during mitosis.

Which of the following statements regarding somatic and germ-line mutations is true?

Gene conversion

An unexpected observation of the outcome of meiosis in the fungus Neurospora, in which the ratio of orange to white products was 6:2 instead of 4:4, demonstrated which process?

abnormal bases

Base excision repair (BER) is the main system used in the repair of ______.

Nonsense mutations

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

A base deletion A base addition

Which changes can cause a frameshift mutation?

Duplications

Which of the following is least likely to occur as a result of a double-strand break?

where two chromosome pieces break and rejoin with other chromosome pieces

A breakpoint refers to the region ______.

half of the gametes ; none of the gametes

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

10-100

In an average human individual, naturally occurring double-strand breaks occur at a rate of ______ per cell per day.

Intergenic suppression

In this figure, two panels are shown. Panel I shows protein A. A first mutation inhibits the function of protein A. In Panel II a second mutation alters protein B to carry out the function of protein A. What is this an example of?

intragenic suppressor

This figure shows an example of a(n)_______________ ______________mutation.

increase generation after generation

Trinucleotide repeat expansions are repeated sequences of three nucleotide bases which ______.