question

A chemical agent that interferes with DNA repair may be considered a mutagen.

answer

True

question

Which of the following statements concerning cancer and mutations is CORRECT? A:Cancer can only occur with a mutation in a somatic cell. B: Usually, multiple mutations are required in different genes to cause cancer. C:None of the other answer options is correct. D:Cancer can only occur with a mutation in a germ cell. E: Usually, a single mutation is all that is required to cause cancer.

answer

B

question

Which of the following point mutations is unlikely to change a protein's ability to function? (Select all that apply.) A:one that occurs in germ cells B: one that creates a new codon that codes for an amino acid of the same size as that coded for by the original codon C: one that occurs in a noncoding region of DNA D:one that creates a new codon code for the same amino acid as the original codon E:one that occurs in somatic cells

answer

C & D

question

In a muscle cell, myosin binds to actin to cause muscle contraction. Researchers have found that rabbit muscle myosin binds to actin from an amoeba. How can this be? A: The differences in myosin between amoeba and rabbits do not affect the actin-binding site of myosin. B: The myosin from amoeba and rabbits is similar due to a distant common ancestor, and the differences between them do not affect the actin binding site. C: The myosin from amoeba and rabbits is similar due to a distant common ancestor. D: Proteins whose functions are important to many types of organisms are more likely to be conserved. E: All of these choices are correct.

answer

E

question

A nonsense mutation:

answer

changes a codon for an amino acid into a codon for chain termination.

question

Deletions that eliminate a multiple of three nucleotides can:

answer

delete amino acids in a polypeptide chain.

question

The human genome contains a family of genes that code for different forms of myosin. How could this gene family have arisen?

answer

The original myosin gene was duplicated, and the resulting copies have diverged.

question

The enzyme _____ repairs 99% of mismatched bases immediately during replication.

answer

DNA Polymerase

question

Which of the following statements applies to frameshift mutations? A: They create a premature stop codon at the site of mutation. B: They cause the insertion or deletion of a single amino acid from the polypeptide chain. C: They are known risk factors in breast cancer, but not colon cancer. D: They are known risk factors in most forms of cancer, including breast and colon cancer. E: They change the amino acid sequence downstream from the mutant site.

answer

E

question

Which of the following statements MOST accurately describes the benefits of the proofreading function of DNA polymerase? A: DNA polymerase can be recruited to recently mutated sites to repair mutations. B: DNA polymerase is always present in the nucleus and can repair all mutations when they occur. C: DNA polymerase can repair most mutations as they occur during DNA replication. D: All DNA mutations can be detected and repaired during DNA replication.

answer

C

question

The most frequent kind of mutation, a point mutation, occurs when:

answer

DNA repair mechanisms fail. a single base pair is replaced by another.

question

The process of gene duplication and divergence refers to:

answer

the creation of gene families, which are similar genes within a species. creating new genes by mutation in duplicates of old genes.

question

Insertions and deletions of single nucleotides:

answer

cause frameshift mutations

question

The enzyme _____ repairs breaks in the DNA sugar-phosphate backbone.

answer

DNA Ligase

question

A family can share a genetic risk of developing cancer if:

answer

a germ-line mutation in one of the genes implicated in the cancer occurred in an ancestor.

question

Which of the following causes breaks in one or both of the sugar-phosphate backbones? A: tobacco smoke B: UV radiation C: exposure to oxidizing agents such as household bleach or hydrogen peroxide D: X-rays

answer

D

question

In the standard genetic code, how many codons for amino acids allow synonymous mutations in the third position?

answer

59

question

A point mutation that causes an amino acid replacement is called a:

answer

nonsynonymous (missense) mutation

question

A point mutation that creates a premature stop codon is called a _____ mutation.

answer

nonsense

question

Which of the following types of mutation is typically harmful? A: gene duplication B: deletion of the centromere C: reciprocal translocation D: gene inversion

answer

B

question

Chromosomes in which the normal order of a block of genes is reversed contain a(n):

answer

inversion

question

A chromosomal mutation in which a segment is missing is called a deletion.

answer

True

question

Point mutations that cause amino acid replacements are called:

answer

nonsynonymous (missense) mutation

question

In the sickle-cell anemia mutation, the 5′-GAG-3′ codon for glutamic acid becomes the 5′-GUG-3′ codon for valine. Assuming a single nucleotide substitution accounts for this mutation, what is the change in the DNA?

answer

3′-CTC-5′/5′-GAG-3′' to 3′-CAC-5′/5′-GTG-3′

question

Some people with blue eyes have a small sector of one eye that is brown. What kind of mutation could cause this color difference?

answer

a somatic mutation late in development

question

Consider the single methionine codon 5′-AUG-3′ in the standard genetic code. Can a single base change in this codon create a synonymous mutation? Can a single base change in this codon create a stop codon?

answer

no; no

question

Why do RNA viruses and retroviruses have such high rates of mutation?

answer

because RNA is more fragile than DNA and is therefore more likely to be damaged because viral polymerases lack a proofreading mechanism

question

You are working in a lab and studying a gene. You notice that many other genes in the same organism code for similar proteins. This is MOST likely the result of:

answer

duplication and divergence.

question

Normally, in corn, genes for waxy and virescent kernel appearance are in the same chromosome. In a certain stock, however, it was found that these two genes are in different chromosomes. Which chromosomal aberration would explain this?

answer

translocation

question

Chronic myelogenous leukemia (CML) is caused when a segment of chromosome 9 and a segment of chromosome 22 both break off and switch places. How is this mutation classified?

answer

reciprocal translocation

question

Only germ-line mutations are transmitted to the progeny.

answer

True

question

When nonhomologous chromosomes exchange parts, a(n) _____ has occurred.

answer

reciprocal translocation

question

_____ mutations are important to the evolutionary process; most cancers result from _____ mutations.

answer

Germline; Somatic

question

Large chromosomal inversions can cause problems in which of the following processes?

answer

meiosis

question

Any heritable change in the genetic material is _____.

answer

a mutation

question

Imagine a gene in which the sequence that is transcribed into a GAG codon, which codes for glutamic acid, is mutated to GUG, which codes for valine. What type of mutation is this?

answer

missense

question

. The American Cancer Society currently estimates that only about 10% of all people with melanoma have a family history of the disease. What factors might contribute to the development of melanoma in the other 90% of patients? A: All of these choices are correct. B: exposure to chemical mutagens C: mutations in a melanocyte D: exposure to solar radiation

answer

A

question

The relatively large number of new mutations that occur in the human genome in each generation is tolerable because:

answer

most of our genome is noncoding DNA, so few mutations affect our proteins.

question

_____ is the process where new genes evolve from duplicates of old ones.

answer

Duplication and divergence

question

Point mutations can impair a protein if they result in a:

answer

nonsense codon. shift in reading frame. nonsynonymous codon.

question

A point mutation that causes no change in the amino acid sequence of a protein is called a:

answer

synonymous (silent) mutation

question

An agent that increases mutation rate is a _____.

answer

mutagen

question

Sickle-cell anemia results from what type of mutation?

answer

missense

question

Movable DNA sequences are called:

answer

transposable elements.

question

Cancer is usually due to:

answer

a series of mutations that occur in a single lineage of somatic cells.

question

Why do data on observable mutant phenotypes underestimate the actual frequency of mutation?

answer

Many mutations are in noncoding regions of the genome. Some mutations in protein-coding regions of the genome are synonymous mutations.

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