Question 1

Although there are 6 billion base pairs of DNA packed in 46 human chromosomes, only _______ percent of the DNA in the human genome codes for proteins.

Accepted Answer

The answer of Although there are 6 billion base pairs...

Question 2

SNPs and STRs are two common markers used in _______.

Accepted Answer

The answer of SNPs and STRs are two common markers...

Question 3

A point mutation

Accepted Answer

A)   is a result of a chromosomal deletion.
B)   is always silent.
C)   does not occur in noncoding regions of DNA.
D)   is a change in a single nucleotide of DNA.
E)   is not transmitted to daughter cells.F) All of the above
G) B) and D)

Question 4

In DNA fingerprinting,

Accepted Answer

A)   DNA is non-specifically cut by nucleases.
B)   DNA is cut by nucleases into fragments of equal size.
C)   DNA fragments are separated by gel electrophoresis based on their charge.
D)   repetitive DNA sequences are often used.
E)   PCR is not useful.F) All of the above
G) B) and D)

Question 5

Gene therapy requires

Accepted Answer

A)   a way to introduce new genes into the patient's cells.
B)   the expression of the introduced gene in vivo.
C)   insertion of the new gene into the host DNA.
D)   identification and isolation of the wild type allele.
E)   All of the aboveF) B) and C)
G) B) and D)

Question 6

Which of the following is true about restriction enzymes?

Accepted Answer

A)   They cut at regular intervals, every 4,000 base pairs.
B)   They prefer to cut at DNA that has been methylated.
C)   EcoRI's restriction site is a palindrome.
D)   All of the above
E)   None of the aboveF) B) and E)
G) A) and B)

Question 7

Expanding triplet repeats

Accepted Answer

A)   occur during DNA replication due to slippage of DNA polymerase.
B)   are caused by errors in DNA synthesis with reverse transcriptase.
C)   can be identified using RFLP mapping.
D)   occur in individuals with a normal number of triplet codons.
E)   Both a and cF) B) and E)
G) B) and C)

Question 8

Duplications and translocations differ in that

Accepted Answer

A)   translocations involve the loss of a chromosomal segment, whereas duplications involve addition of an entire chromosome.
B)   duplications involve the breakage and swapping of DNA segments on homologous chromosomes, whereas translocations are reciprocal exchanges on nonhomologous chromosomes.
C)   translocations involve the breakage and insertion of DNA segments in reverse order, whereas duplications are the breakage at different points on the chromosome.
D)   duplications lead to duplications of the chromosome, whereas translocations involve swapping of chromosome segments.
E)   translocations result in loss of chromosomal segments, whereas duplications result in significant additions to nonhomologous chromosomes.F) C) and D)
G) A) and E)

Question 9

Conditional mutations

Accepted Answer

A)   are mutations that are expressed in wild-type cells.
B)   are deletion mutations.
C)   are analyzed under permissive and restrictive conditions.
D)   produce gene products that are nonfunctional under all conditions.
E)   can be analyzed only under restrictive conditions.F) B) and E)
G) A) and E)

Question 10

Breaking and rejoining of chromosomes can lead to

Accepted Answer

A)   deletions.
B)   duplications.
C)   inversions.
D)   translocations.
E)   All of the aboveF) A) and B)
G) B) and D)

Question 11

Genetic screening

Accepted Answer

A)   has been used to treat embryos carrying a mutant allele.
B)   requires that gene sequences are the same in affected and unaffected individuals.
C)   has been used to identify fathers who are carriers for X-linked alleles.
D)   has been used to identify mutant alleles in embryos.
E)   requires dissimilarity between the alleles being tested and those that are linked to a particular disease.F) A) and C)
G) B) and D)

Question 12

Chemical mutagens should also be carcinogens. Some compounds that did not increase the mutation rate of the bacterium E. coli are nonetheless potent carcinogens in animals. Why?

Accepted Answer

A)   The genetic code in the bacterium differs from that in animals.
B)   Bacterial genes are often arranged in operons.
C)   Some chemicals are not mutagenic or carcinogenic unless they are altered in the ER of animal cells.
D)   Many animal cell genes have introns.
E)   Animals may have germ line mutations.F) B) and D)
G) C) and D)

Question 13

The type of mutation that involves the insertion or a deletion of a single base in the coding region of proteins is called

Accepted Answer

A)   a missense mutation.
B)   a nonsense mutation.
C)   a point mutation.
D)   an aberration.
E)   None of the aboveF) C) and D)
G) A) and D)

Question 14

The screening technique that uses oligonucleotide probes to screen for genetic diseases is _______.

Accepted Answer

allele-spe...

Question 15

In fragile-X syndrome, males are said to be _______; grandchildren from their daughters have _______ repeats than their daughters have.

Accepted Answer

A)   imprinted; more
B)   imprinted; fewer
C)   premutated; more
D)   premutated; fewer
E)   multifactorial; moreF) A) and E)
G) A) and D)

Question 16

Restriction enzymes

Accepted Answer

A)   cleave DNA at sequence-specific sites.
B)   are called restriction enzymes because they restrict the range of viruses that can attack a bacterial species.
C)   do not cut the host bacterium's DNA.
D)   are essential tools in molecular biology.
E)   All of the aboveF) A) and C)
G) A) and B)

Question 17

Damage to DNA can be caused by _______ absorbed by thymine in DNA, causing interbase covalent bonds.

Accepted Answer

A)   X rays
B)   cosmic radiation
C)   ultraviolet radiation
D)   smoke
E)   cigarettesF) B) and E)
G) B) and D)

Question 18

_______ is caused by a single base substitution that changes one amino acid in a polypeptide. Individuals who are homozygous for this disease have defective, misshapen red blood cells.

Accepted Answer

A)   Duchenne muscular dystrophy
B)   Sickle-cell anemia
C)   Kuru
D)   Cystic fibrosis
E)   Familial hypercholesterolemiaF) C) and D)
G) A) and E)

Question 19

Metabolic disorders are

Accepted Answer

A)   caused by mutations in centromeres.
B)   the result of mutations in genes encoding enzymes that are required to synthesize particular compounds in the cell (such as an amino acid) .
C)   due to abnormal membrane proteins that transport chloride ions.
D)   caused by prions.
E)   All of the aboveF) B) and D)
G) A) and B)

Question 20

People with sickle-cell disease have _______ abnormality.

Accepted Answer

A)   a phenylalanine hydrolyase
B)   an oncogene
C)   a cholesterol transport
D)   a hemoglobin
E)   None of the aboveF) A) and B)
G) D) and E)

Exam 15: Gene Mutation and Molecular Medicine

Restriction enzymes

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Conditional mutations

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Gene therapy requires

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People with sickle-cell disease have _______ abnormality.

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Which of the following is true about restriction enzymes?

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In fragile-X syndrome, males are said to be _______; grandchildren from their daughters have _______ repeats than their daughters have.

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Genetic screening

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The screening technique that uses oligonucleotide probes to screen for genetic diseases is _______.

Correct Answerverifiedallele-spe...View AnswerShow Answer

Although there are 6 billion base pairs of DNA packed in 46 human chromosomes, only _______ percent of the DNA in the human genome codes for proteins.

Correct AnswerverifiedShow Answer

SNPs and STRs are two common markers used in _______.

Correct AnswerverifiedShow Answer

Expanding triplet repeats

Correct AnswerverifiedShow Answer

In DNA fingerprinting,

Correct AnswerverifiedShow Answer

Breaking and rejoining of chromosomes can lead to

Correct AnswerverifiedShow Answer

Chemical mutagens should also be carcinogens. Some compounds that did not increase the mutation rate of the bacterium E. coli are nonetheless potent carcinogens in animals. Why?

Correct AnswerverifiedShow Answer

_______ is caused by a single base substitution that changes one amino acid in a polypeptide. Individuals who are homozygous for this disease have defective, misshapen red blood cells.

Correct AnswerverifiedShow Answer

Duplications and translocations differ in that

Correct AnswerverifiedShow Answer

A point mutation

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The type of mutation that involves the insertion or a deletion of a single base in the coding region of proteins is called

Correct AnswerverifiedShow Answer

Metabolic disorders are

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Damage to DNA can be caused by _______ absorbed by thymine in DNA, causing interbase covalent bonds.

Correct AnswerverifiedShow Answer

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In fragile-X syndrome, males are said to be _; grandchildren from their daughters have _ repeats than their daughters have.

Correct Answer
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allele-spe...
View Answer

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