Quiz 13: Mutations and Genetic Testing

Chorionic villus sampling carries less risk of causing miscarriage than amniocentesis.

A translocation chromosomal mutation is the exchange of segments between two homologous chromosomes.

Testing for a protein may help reveal whether or not an individual has a genetic disorder.

Alleles associated with known genetic disorders can be detected using DNA microarray analysis.

To perform an in vivo gene therapy treatment, cells are removed from the patient's body, normal genes are added to them, and then the cells are returned to the patient's body.

An extra three nucleotides inserted into a gene will cause a frameshift mutation.

Mutations within genes always result in nonfunctional proteins.

Genetic counseling can help determine the risk of inheriting sickle cell disease in a family.

Which of the following is considered a mutagen? Check all that apply. A) X-rays B) UV light C) Transposons D) alleles E) pesticides

A chromosome normally has the following sequence of genes: f-g-h-i-j-k-l-m. Upon testing, an individual is found to have the following sequence: f-g-h-i-j-k-k-j-i-l-m. What kind(s) of chromosomal mutation(s) does this chromosome have? Check all that apply. A) deletion B) duplication C) translocation D) inversion E) frameshift

A karyotype shows chromosomes arranged by A) banding pattern, size, and shape. B) shape, size, and complexity. C) complexity, radius, and length. D) length, structure, and color. E) color, width, and length.

Chromosomes for karyotyping are often obtained from a blood sample. Red blood cells, however, cannot be used for this purpose because A) they are too small. B) they lack nuclei. C) white blood cells are much more common. D) they have abnormal chromosomes. E) they are difficult to isolate.

Amniocentesis may be preferred over chorionic villus sampling (CVS) for karyotyping because A) CVS takes much longer to obtain a karyotype. B) CVS is a more invasive procedure. C) amniocentesis has a lower risk of miscarriage than CVS. D) amniocentesis can be performed more quickly than CVS. E) a larger amount of tissue may be obtained through amniocentesis.

Chromosome 7 may lose an end piece resulting in Williams syndrome. This is an example of a chromosomal A) inversion. B) duplication. C) deletion. D) translocation. E) epigenetic inheritance.

A missing piece of chromosome 5 may result in a child whose glottis and larynx do not develop properly, resulting in an abnormal cry. This is called A) cri du chat syndrome. B) Huntington syndrome. C) Klinefelter syndrome. D) inv dup 15 syndrome. E) Down syndrome.

Inversions are chromosomal mutations that A) always result in a syndrome. B) neither increase nor decrease the amount of genetic material in the cell. C) rarely cause deletions or duplications during gamete formation when crossing-over occurs. D) result from duplication of a portion of a chromosome. E) never disrupt gene regulation or cause physical abnormalities.

A parent carries a deletion on one of the two homologouschromosomes. What is the probability of this individual's child carrying the same deletion? A) 0% B) 25% C) 50% D) 75% E) 100%

Which of the following syndromes is caused by a translocation? A) Alagille syndrome B) inv dup 15 syndrome C) Williams syndrome D) cri du chat syndrome E) Turner syndrome

A child with bluish-purple skin is found to lack the enzyme diaphorase and is subsequently diagnosed with which genetic disorder? A) methemoglobinemia B) Duchenne muscular dystrophy C) Marfan syndrome D) sickle-cell disease E) color blindness

A known abnormality in a gene's sequence that can be linked to a genetic disease is called a(n) A) genetic profile. B) enzyme. C) genetic marker. D) DNA microarray. E) genomic DNA.

A genetic profile includes A) the location of all known genes in the human genome. B) the entire base sequence of an individual's genome. C) all of an individual's normal genes. D) an individual's complete genotype, including mutations. E) all of an individual's genetic markers.

What kinds of mutations can be revealed through ultrasound? A) Some chromosomal abnormalities, such as Down syndrome and Edwards syndrome, and a few other known inherited disorders. B) The genetic profile, including any mutant gene alleles the fetus may have. C) All chromosomal mutations, including deletions, duplications, inversions, and translocations. D) Only larger chromosomal mutations, such as the large deletion seen in individuals with cri du chat syndrome. E) Only inherited genetic disorders caused by single gene mutations.

An embryo produced by in vitro fertilization (IVF) may be tested for genetic disorders prior to implantation. How is this accomplished? A) Fetal cells are recovered from the mother's blood, and the DNA is analyzed. B) Amniocentesis or chorionic villus sampling is performed, and a karyotype assembled. C) A polar body is isolated and its DNA amplified by PCR for analysis. D) A single cell is removed from a 6- to 8-celled embryo, and its DNA analyzed. E) Blood is drawn from the embryo for genetic marker analysis.

A DNA microarray detects A) uncommon forms of alleles, or mutants, associated with disease. B) an individual's complete genotype, including all the various mutations. C) chromosomal abnormalities, such as duplications or deletions. D) fetal cells in the mother's blood. E) viral DNA in an individual's cells.

A person with familial hypercholesterolemia is participating in an ex vivo gene therapy trial. The procedure involves A) infecting a portion of the person's liver with a retrovirus containing a normal gene for a cholesterol receptor. B) spraying the normal gene for the cholesterol receptor into the nose. C) insertion of the cholesterol receptor gene into a virus, then injecting the virus into the person. D) removing a piece of the person's liver, infecting it with a retrovirus containing the normal cholesterol receptor gene, and replacing the liver cells following treatment. E) transplanting a normal liver into the individual.

What are the current known methods of delivering genes to cells for gene therapy? A) viruses, liposomes, and nasal sprays B) viruses, nasal sprays, and gene guns C) liposomes, nasal sprays, and chemical transformation D) nasal sprays, liposomes, and gene guns E) viruses and gene guns

Ex vivo gene therapy differs from in vivo gene therapy in that A) ex vivo gene therapy involves directly introducing the gene into the body. B) in vivo gene therapy involves directly introducing the gene into the body. C) in vivo gene therapy only employs viruses for gene transfer. D) ex vivo gene therapy only employs viruses for gene transfer. E) ex vivo gene therapy can employ viruses, nasal sprays, or liposomes for gene transfer, but only liposomes may be used for in vivo gene therapy.

Gene therapy would not be an effective treatment for Down syndrome because A) scientists do not know which faulty genes cause the syndrome. B) Down syndrome results from having an extra chromosome with over a thousand genes. C) liposomes and nasal sprays cannot be used due to abnormalities in the respiratory tract of Down syndrome individuals. D) Down syndrome is not a genetic disorder. E) the gene therapy treatment could not be performed on an adult individual.

Which one of the following diseases or disorders has not been treated using gene therapy methods? A) rheumatoid arthritis B) familial hypercholesterolemia C) cri du chat syndrome D) cystic fibrosis E) SCID

A transposon may cause a mutation if it A) jumps into an exon of another gene. B) jumps into an intron of another gene. C) jumps into an intergenic DNA sequence. D) remains trapped within an intergenic DNA sequence. E) interacts with a physical mutagen.

A silent mutation is more likely to occur as a result of A) a frameshift mutation. B) a point mutation that does not change the amino acid encoded within the gene. C) the movement of a transposon into an exon. D) a point mutation that alters the amino acid encoded within the gene. E) a large dose of radiation.

Mutations are relatively uncommon because A) DNA repair enzymes often fix errors. B) physical mutagens such as X-rays seldom damage DNA. C) DNA is able to repair itself over time. D) frameshift mutations occur very frequently. E) transposons are constantly moving throughout the genome.

In what way do transposons cause mutations to occur? A) Transposons move within and between chromosomes, disrupting the genes. B) Transposons cause large sections of the gene to be deleted from the chromosome, making it useless. C) Transposons cause sections of the chromosome to make multiple copies of the same nucleotide. D) Transposons produce proteins that conflict with the normal functioning proteins of the cell. E) Transposons cause nonfunctional genes to be "woken up" and become functional.

Transposons have been discovered in which of the following groups? A) bacteria B) plants C) humans D) fruit flies E) All of the above

Which genetic disorder is due to a deletion on chromosome 7? A) Williams syndrome B) cri du chat syndrome C) Alagille syndrome D) Down syndrome E) cancer

During DNA replication, the original strand (ATTCGCGATTTA) was replicated as (ATTCGGATTTA). What type of mutation is present? A) deletion B) duplication C) transposon D) translocation E) None of these mutations have taken place.

Which of the following consequences can arise as the result of a chromosomal inversion? A) The inverted sequence of alleles can lead to altered gene activity, but only if it disrupts the control of gene expression. B) The additional nucleotides added to the allele can cause it to produce an additional protein. C) The nucleotides that have been deleted from the allele will cause the new amino acid chain to be shortened. D) The multiple copies of the adenine nucleotide that have been added will increase the number of amino acids added to the chain. E) There are no consequences due to a chromosomal inversion.

In hemoglobin, the shift from glutamic acid to valine is considered what type of mutation? A) point mutation B) frameshift mutation C) transposons D) deletion E) duplication

What structure is often used to deliver copies of genes into cells? A) viruses B) PCR C) bacteria D) prions E) hypodermic needles

Which structure is used in the new treatment of rheumatoid arthritis? A) adenovirus B) SCID C) bacteriophage D) hypodermic needles E) None of these structures are used in the treatment of rheumatoid arthritis.

Which type of chromosomal mutation will lead to Alagille syndrome? A) translocation B) duplication C) inversion D) frameshift E) point mutation

Which human disorder is being treated with gene therapy? A) severe combined immunodeficiency (SCID) B) familial hypercholesterolemia C) cancer D) cystic fibrosis E) All of these are being treated with gene therapy.