Question 1

Point mutations are referred to as missense, silent, frameshift, or nonsense when they change the protein-coding potential of a gene. What is another group of mutations that may have important consequences for gene expression?

Accepted Answer

A)   mutations that exist outside coding sequences
B)   combinations of missense and silent mutations
C)   combinations of nonsense and silent mutations
D)   mutations that alter the amino acid sequence of a gene
E)   mutations that shift the reading frame of a geneF) D) and E)
G) B) and D)

Question 2

Why might a point mutation in DNA make a difference in the level of a protein's activity?

Accepted Answer

A)   It might result in a chromosomal translocation.
B)   It might exchange one stop codon for another stop codon.
C)   It might delay the rate of DNA replication.
D)   It might substitute a different amino acid in the active site.
E)   It might substitute the N-terminus of the polypeptide for the C-terminus.F) A) and C)
G) A) and E)

Question 3

Which of the following mutations would be most likely to have a harmful effect on an organism?

Accepted Answer

A)   a nucleotide-pair substitution
B)   a deletion of three nucleotides near the middle of a gene
C)   a single nucleotide deletion in the middle of an intron
D)   a single nucleotide deletion near the end of the coding sequence
E)   a single nucleotide insertion downstream of, and close to, the start of the coding sequenceF) B) and E)
G) A) and B)

Question 4

In the first step of their experiments, Jacob and Monod treated E. coli cells with ultraviolet light or X-rays to ________.

Accepted Answer

A)   decrease the rate of gene expression
B)   induce DNA repair enzymes
C)   increase the frequency of mutations in all genes
D)   selectively mutate specific genes, leaving all other genes unmutatedE) A) and B)
F) A) and C)

Question 5

Genotype is to ________ as phenotype is to ________.

Accepted Answer

A)   DNA base sequence; physical traits that are products of the proteins produced
B)   heredity; DNA base sequence
C)   gene regulation; translation
D)   transcription; amino acid sequenceE) A) and B)
F) B) and C)

Question 6

In the Morse code, a series of dots and dashes code for letters of the alphabet. How is this analogous to the genetic code?

Accepted Answer

A)   There is complementarity in the genetic code (A is complementary to T, and C is complementary to G) .
B)   The bases that make up DNA are coded by the sugar-phosphate backbone.
C)   The machinery involved in DNA synthesis is analogous to the telegraph equipment used in sending Morse code.
D)   The bases of DNA code for the more complex amino acid sequence of the proteins in cells.E) B) and D)
F) All of the above

Question 7

How does the simple primary and secondary structure of DNA hold the information needed to code for the many features of multicellular organisms?

Accepted Answer

A)   The hydrogen bonding among backbone constituents carries coded information.
B)   The base sequence of DNA carries the information needed to code for proteins.
C)   The width of the double helix changes at each gene due to differences in hydrogen bonds.
D)   The amino acids that make up the DNA molecule contain the information needed to make cellular proteins.E) All of the above
F) C) and D)

Question 8

The following question(s)  refer to this table of codons. 
-A peptide has the sequence NH2-phe-pro-lys-gly-phe-pro-COOH. Which of the following sequences in the coding strand of the DNA could code for this peptide?

Accepted Answer

A)   3' UUU-CCC-AAA-GGG-UUU-CCC
B)   3' AUG-AAA-GGG-TTT-CCC-AAA-GGG
C)   5' TTT-CCC-AAA-GGG-TTT-CCC
D)   5' GGG-AAA-TTT-AAA-CCC-ACT-GGG
E)   5' ACT-TAC-CAT-AAA-CAT-TAC-UGAF) B) and E)
G) A) and E)

Question 9

The mutation resulting in sickle cell disease changes one base pair of DNA so that a codon now codes for a different amino acid, making it an example of a ________.

Accepted Answer

A)   nonsense mutation
B)   frameshift mutation
C)   silent mutation
D)   missense mutationE) None of the above
F) B) and D)

Question 10

Which of the following is NOT synthesized from a DNA template?

Accepted Answer

A)   messenger RNA
B)   amino acids
C)   transfer RNA
D)   ribosomal RNAE) B) and C)
F) A) and B)

Question 11

A mutation that results in premature termination of translation ________.

Accepted Answer

A)   is a silent mutation
B)   is a nonsense mutation
C)   usually has no effect on the function of the protein
D)   is a missense mutationE) All of the above
F) A) and B)

Question 12

Knockout mice have been genetically altered to knock out specific genes. How are these mice most often used in research?

Accepted Answer

A)   to study DNA replication in the defective genes (those that have been altered) 
B)   to determine the role of proteins coded for by those genes that are knocked out
C)   to examine defects in DNA structure in those regions that have been altered
D)   to study the effect of radiation on DNAE) A) and B)
F) A) and C)

Question 13

A particular triplet of bases in the template strand of DNA is 5' AGT 3'. The corresponding codon for the mRNA transcribed is ________.

Accepted Answer

A)   3' UCA 5'
B)   3' UGS 5'
C)   5' TCA 3'
D)   3' ACU 5'
E)   either UCA or TCA, depending on wobble in the first baseF) A) and C)
G) B) and D)

Question 14

Refer to the associated figure. In the branched metabolic pathway indicated in the figure, if enzyme 3 is defective and the amount of each enzyme is constant, you might expect to see an increase in the amount of which intermediate or product?

Accepted Answer

A)   E
B)   B
C)   F
D)   DE) A) and C)
F) B) and D)

Question 15

HIV, the causative agent of AIDS, is a retrovirus. A retrovirus ________.

Accepted Answer

A)   uses DNA as a template in the process of translation
B)   makes proteins directly from RNA
C)   uses reverse transcriptase to make DNA from RNA
D)   is a cellular virus that uses ribosomes to reproduce inside a living cellE) B) and D)
F) B) and C)

Question 16

Consider the following section of mRNA:
UCUGAUGGGCUUU…
Beginning with the start codon, which amino acids, in order, are coded for by this section of mRNA? Consult the codon table provided if necessary.

Accepted Answer

A)   serine, aspartic acid, glycine, leucine
B)   methionine, glycine, phenylalanine
C)   methionine, valine, glycine, phenylalanine
D)   threonine, methionine, glycineE) B) and D)
F) A) and D)

Question 17

According to the central dogma, what molecule should go in the blank?
DNA → ________ → Proteins

Accepted Answer

A)   mtDNA
B)   rRNA
C)   mRNA
D)   tRNAE) B) and D)
F) None of the above

Question 18

Which of the following types of mutation, resulting in an error in the mRNA just after the AUG start of translation, is likely to have the most serious effect on the polypeptide product?

Accepted Answer

A)   a deletion of a codon
B)   a deletion of two nucleotides
C)   a substitution of the third nucleotide in an ACC codon
D)   a substitution of the first nucleotide of a GGG codon
E)   an insertion of a codonF) B) and D)
G) C) and E)

Question 19

In the process of transcription, ________.

Accepted Answer

A)   DNA is replicated
B)   RNA is synthesized
C)   proteins are synthesized
D)   mRNA attaches to ribosomesE) None of the above
F) A) and D)

Question 20

Refer to the associated figure. A branched metabolic pathway synthesizes two related amino acids (D and F)  If there is a genetic defect, resulting in a nonfunctional enzyme (3) , how could you ensure that adequate amounts of the amino acid F are synthesized?

Accepted Answer

A)   supplement intermediate B
B)   supplement intermediate C
C)   add enzyme 2 to the medium
D)   supplement with intermediate EE) C) and D)
F) B) and D)

Exam 16: How Genes Work

According to the central dogma, what molecule should go in the blank? DNA → ________ → Proteins

Correct AnswerverifiedShow Answer

Which of the following is NOT synthesized from a DNA template?

Correct AnswerverifiedShow Answer

Which of the following types of mutation, resulting in an error in the mRNA just after the AUG start of translation, is likely to have the most serious effect on the polypeptide product?

Correct AnswerverifiedShow Answer

The mutation resulting in sickle cell disease changes one base pair of DNA so that a codon now codes for a different amino acid, making it an example of a ________.

Correct AnswerverifiedShow Answer

Refer to the associated figure. A branched metabolic pathway synthesizes two related amino acids (D and F) If there is a genetic defect, resulting in a nonfunctional enzyme (3) , how could you ensure that adequate amounts of the amino acid F are synthesized?

Correct AnswerverifiedShow Answer

The following question(s) refer to this table of codons. -A peptide has the sequence NH2-phe-pro-lys-gly-phe-pro-COOH. Which of the following sequences in the coding strand of the DNA could code for this peptide?

Correct AnswerverifiedShow Answer

A particular triplet of bases in the template strand of DNA is 5' AGT 3'. The corresponding codon for the mRNA transcribed is ________.

Correct AnswerverifiedShow Answer

Why might a point mutation in DNA make a difference in the level of a protein's activity?

Correct AnswerverifiedShow Answer

HIV, the causative agent of AIDS, is a retrovirus. A retrovirus ________.

Correct AnswerverifiedShow Answer

Knockout mice have been genetically altered to knock out specific genes. How are these mice most often used in research?

Correct AnswerverifiedShow Answer

In the process of transcription, ________.

Correct AnswerverifiedShow Answer

A mutation that results in premature termination of translation ________.

Correct AnswerverifiedShow Answer

Refer to the associated figure. In the branched metabolic pathway indicated in the figure, if enzyme 3 is defective and the amount of each enzyme is constant, you might expect to see an increase in the amount of which intermediate or product?

Correct AnswerverifiedShow Answer

In the Morse code, a series of dots and dashes code for letters of the alphabet. How is this analogous to the genetic code?

Correct AnswerverifiedShow Answer

Point mutations are referred to as missense, silent, frameshift, or nonsense when they change the protein-coding potential of a gene. What is another group of mutations that may have important consequences for gene expression?

Correct AnswerverifiedShow Answer

Genotype is to ________ as phenotype is to ________.

Correct AnswerverifiedShow Answer

Which of the following mutations would be most likely to have a harmful effect on an organism?

Correct AnswerverifiedShow Answer

How does the simple primary and secondary structure of DNA hold the information needed to code for the many features of multicellular organisms?

Correct AnswerverifiedShow Answer

In the first step of their experiments, Jacob and Monod treated E. coli cells with ultraviolet light or X-rays to ________.

Correct AnswerverifiedShow Answer

Consider the following section of mRNA: UCUGAUGGGCUUU… Beginning with the start codon, which amino acids, in order, are coded for by this section of mRNA? Consult the codon table provided if necessary.

Correct AnswerverifiedShow Answer

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Genotype is to as phenotype is to .

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