Question 1

When the ribosome reaches a stop codon on the mRNA, no corresponding tRNA enters the A site. If the translation reaction were to be experimentally stopped at this point, which of the following would you be able to isolate?

Accepted Answer

A)   an assembled ribosome with a polypeptide attached to the tRNA in the P site
B)   separated ribosomal subunits, a polypeptide, and free tRNA
C)   an assembled ribosome with a separated polypeptide
D)   separated ribosomal subunits with a polypeptide attached to the tRNA
E)   a cell with fewer ribosomes

Question 2

-The tRNA shown in the figure has its 3' end projecting beyond its 5' end. What will occur at this 3' end?

Accepted Answer

A)   The codon and anticodon complement one another.
B)   The amino acid binds covalently.
C)   The excess nucleotides (ACC
A)   will be cleaved off at the ribosome.
D)   The small and large subunits of the ribosome will attach to it.
E)   The 5' cap of the mRNA will become covalently bound.

Question 3

Garrod hypothesized that "inborn errors of metabolism" such as alkaptonuria occur because

Accepted Answer

A)   metabolic enzymes require vitamin cofactors, and affected individuals have significant nutritional deficiencies.
B)   enzymes are made of DNA, and affected individuals lack DNA polymerase.
C)   many metabolic enzymes use DNA as a cofactor, and affected individuals have mutations that prevent their enzymes from interacting efficiently with DNA.
D)   certain metabolic reactions are carried out by ribozymes, and affected individuals lack key splicing factors.
E)   genes dictate the production of specific enzymes, and affected individuals have genetic defects that cause them to lack certain enzymes.

Question 4

During splicing, which molecular component of the spliceosome catalyzes the excision reaction?

Accepted Answer

A)   protein
B)   DNA
C)   RNA
D)   lipid
E)   sugar

Question 5

The process of translation, whether in prokaryotes or eukaryotes, requires tRNAs, amino acids, ribosomal subunits, and which of the following?

Accepted Answer

A)   polypeptide factors plus ATP
B)   polypeptide factors plus GTP
C)   polymerases plus GTP
D)   SRP plus chaperones
E)   signal peptides plus release factor

Question 6

Use the following model of a eukaryotic transcript to answer the next few questions.
5' UTR E₁ I₁ E₂ I₂ E₃ I₃ E₄ UTR 3'
-Which of the following is a useful feature of introns for this model?

Accepted Answer

A)   They are translated into small polypeptides.
B)   They become parts of snRNPs.
C)   Each intron has enzymatic properties.
D)   Introns allow exon shuffling.
E)   Introns protect exon structure.

Question 7

Which of the following mutations is most likely to cause a phenotypic change?

Accepted Answer

A)   a duplication of all or most introns
B)   a large inversion whose ends are each in intergenic regions
C)   a nucleotide substitution in an exon coding for a transmembrane domain
D)   a single nucleotide deletion in an exon coding for an active site
E)   a frameshift mutation one codon away from the 3' end of the nontemplate strand

Question 8

The following questions 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-UGA

Question 9

Which of the following nucleotide triplets best represents a codon?

Accepted Answer

A)   a triplet separated spatially from other triplets
B)   a triplet that has no corresponding amino acid
C)   a triplet at the opposite end of tRNA from the attachment site of the amino acid
D)   a triplet in the same reading frame as an upstream AUG
E)   a sequence in tRNA at the 3' end

Question 10

The following question refers to this figure of a simple metabolic pathway:
 
-A mutation results in a defective enzyme A. Which of the following would be a consequence of that mutation?

Accepted Answer

A)   an accumulation of A and no production of B and C
B)   an accumulation of A and B and no production of C
C)   an accumulation of B and no production of A and C
D)   an accumulation of B and C and no production of A
E)   an accumulation of C and no production of A and B

Question 11

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 codon

Question 12

A frameshift mutation could result from

Accepted Answer

A)   a base insertion only.
B)   a base deletion only.
C)   a base substitution only.
D)   deletion of three consecutive bases.
E)   either an insertion or a deletion of a base.

Question 13

Which small-scale mutation would be most likely to have a catastrophic effect on the functioning of a protein?

Accepted Answer

A)   a base substitution
B)   a base deletion near the start of a gene
C)   a base deletion near the end of the coding sequence, but not in the terminator codon
D)   deletion of three bases near the start of the coding sequence, but not in the initiator codon
E)   a base insertion near the end of the coding sequence, but not in the terminator codon

Question 14

In the structural organization of many eukaryotic genes, individual exons may be related to which of the following?

Accepted Answer

A)   the sequence of the intron that immediately precedes each exon
B)   the number of polypeptides making up the functional protein
C)   the various domains of the polypeptide product
D)   the number of restriction enzyme cutting sites
E)   the number of start sites for transcription

Question 15

Use the following information to answer the next few questions.
A transfer RNA (#1)  attached to the amino acid lysine enters the ribosome. The lysine binds to the growing polypeptide on the other tRNA (#2)  in the ribosome already.
-Which component is not directly involved in translation?

Accepted Answer

A)   mRNA
B)   DNA
C)   tRNA
D)   ribosomes
E)   GTP

Question 16

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' UGA 5'.
C)   5' TCA 3'.
D)   3' ACU 5'.
E)   either UCA or TCA, depending on wobble in the first base.

Question 17

What is the function of GTP in translation?

Accepted Answer

A)   GTP energizes the formation of the initiation complex, using initiation factors.
B)   GTP hydrolyzes to provide phosphate groups for tRNA binding.
C)   GTP hydrolyzes to provide energy for making peptide bonds.
D)   GTP supplies phosphates and energy to make ATP from ADP.
E)   GTP separates the small and large subunits of the ribosome at the stop codon.

Question 18

Use this representation to answer the following questions.
DNA template strand 5' ____________________________ 3'
DNA complementary strand 3' ____________________________ 5'
-Given the locally unwound double strand above, in which direction does the RNA polymerase move?

Accepted Answer

A)   3' → 5' along the template strand
B)   5' → 3' along the template strand
C)   3' → 5' along the complementary strand
D)   5' → 3' along the complementary strand
E)   5' → 3' along the double-stranded DNA

Question 19

The following information should be used for the next few questions.
A part of an mRNA molecule with the following sequence is being read by a ribosome: 5' CCG-ACG 3' (mRNA) . The following charged transfer RNA molecules (with their anticodons shown in the 3' to 5' direction)  are available. Two of them can correctly match the mRNA so that a dipeptide can form.
 
-The anticodon loop of the first tRNA that will complement this mRNA is

Accepted Answer

A)   3' GGC 5'
B)   5' GGC 3'
C)   5' ACG 3'
D)   5' UGC 3'
E)   3' UGC 5'

Question 20

RNA polymerase in a prokaryote is composed of several subunits. Most of these subunits are the same for the transcription of any gene, but one, known as sigma, varies considerably. Which of the following is the most probable advantage for the organism of such sigma switching?

Accepted Answer

A)   It might allow the transcription process to vary from one cell to another.
B)   It might allow the polymerase to recognize different promoters under certain environmental conditions.
C)   It could allow the polymerase to react differently to each stop codon.
D)   It could allow ribosomal subunits to assemble at faster rates.
E)   It could alter the rate of translation and of exon splicing.

Exam 17: From Gene to Protein

Correct Answer
verified

Use the following information to answer the next few questions. A transfer RNA (#1) attached to the amino acid lysine enters the ribosome. The lysine binds to the growing polypeptide on the other tRNA (#2) in the ribosome already. -Which component is not directly involved in translation?

Correct Answer
verified

Use the following model of a eukaryotic transcript to answer the next few questions. 5' UTR E₁ I₁ E₂ I₂ E₃ I₃ E₄ UTR 3' -Which of the following is a useful feature of introns for this model?

Correct Answer
verified

When the ribosome reaches a stop codon on the mRNA, no corresponding tRNA enters the A site. If the translation reaction were to be experimentally stopped at this point, which of the following would you be able to isolate?

Correct Answer
verified

What is the function of GTP in translation?

Correct Answer
verified

Which of the following mutations is most likely to cause a phenotypic change?

Correct Answer
verified

The process of translation, whether in prokaryotes or eukaryotes, requires tRNAs, amino acids, ribosomal subunits, and which of the following?

Correct Answer
verified

Which small-scale mutation would be most likely to have a catastrophic effect on the functioning of a protein?

Correct Answer
verified

The following questions 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 Answer
verified

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 Answer
verified

Which of the following nucleotide triplets best represents a codon?

Correct Answer
verified

-The tRNA shown in the figure has its 3' end projecting beyond its 5' end. What will occur at this 3' end?

Correct Answer
verified

The following question refers to this figure of a simple metabolic pathway: -A mutation results in a defective enzyme A. Which of the following would be a consequence of that mutation?

Correct Answer
verified

In the structural organization of many eukaryotic genes, individual exons may be related to which of the following?

Correct Answer
verified

A frameshift mutation could result from

Correct Answer
verified

RNA polymerase in a prokaryote is composed of several subunits. Most of these subunits are the same for the transcription of any gene, but one, known as sigma, varies considerably. Which of the following is the most probable advantage for the organism of such sigma switching?

Correct Answer
verified

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

Correct Answer
verified

During splicing, which molecular component of the spliceosome catalyzes the excision reaction?

Correct Answer
verified

Use this representation to answer the following questions. DNA template strand 5' 3' DNA complementary strand 3' 5' -Given the locally unwound double strand above, in which direction does the RNA polymerase move?

Correct Answer
verified

Garrod hypothesized that "inborn errors of metabolism" such as alkaptonuria occur because

Correct Answer
verified

Exam 17: From Gene to Protein

Correct AnswerverifiedShow Answer

Use the following information to answer the next few questions. A transfer RNA (#1) attached to the amino acid lysine enters the ribosome. The lysine binds to the growing polypeptide on the other tRNA (#2) in the ribosome already. -Which component is not directly involved in translation?

Correct AnswerverifiedShow Answer

Use the following model of a eukaryotic transcript to answer the next few questions. 5' UTR E₁ I₁ E₂ I₂ E₃ I₃ E₄ UTR 3' -Which of the following is a useful feature of introns for this model?

Correct AnswerverifiedShow Answer

When the ribosome reaches a stop codon on the mRNA, no corresponding tRNA enters the A site. If the translation reaction were to be experimentally stopped at this point, which of the following would you be able to isolate?

Correct AnswerverifiedShow Answer

What is the function of GTP in translation?

Correct AnswerverifiedShow Answer

Which of the following mutations is most likely to cause a phenotypic change?

Correct AnswerverifiedShow Answer

The process of translation, whether in prokaryotes or eukaryotes, requires tRNAs, amino acids, ribosomal subunits, and which of the following?

Correct AnswerverifiedShow Answer

Which small-scale mutation would be most likely to have a catastrophic effect on the functioning of a protein?

Correct AnswerverifiedShow Answer

The following questions 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

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

Which of the following nucleotide triplets best represents a codon?

Correct AnswerverifiedShow Answer

-The tRNA shown in the figure has its 3' end projecting beyond its 5' end. What will occur at this 3' end?

Correct AnswerverifiedShow Answer

The following question refers to this figure of a simple metabolic pathway: -A mutation results in a defective enzyme A. Which of the following would be a consequence of that mutation?

Correct AnswerverifiedShow Answer

In the structural organization of many eukaryotic genes, individual exons may be related to which of the following?

Correct AnswerverifiedShow Answer

A frameshift mutation could result from

Correct AnswerverifiedShow Answer

RNA polymerase in a prokaryote is composed of several subunits. Most of these subunits are the same for the transcription of any gene, but one, known as sigma, varies considerably. Which of the following is the most probable advantage for the organism of such sigma switching?

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

During splicing, which molecular component of the spliceosome catalyzes the excision reaction?

Correct AnswerverifiedShow Answer

Use this representation to answer the following questions. DNA template strand 5' ____________________________ 3' DNA complementary strand 3' ____________________________ 5' -Given the locally unwound double strand above, in which direction does the RNA polymerase move?

Correct AnswerverifiedShow Answer

Garrod hypothesized that "inborn errors of metabolism" such as alkaptonuria occur because

Correct AnswerverifiedShow Answer

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verified

Correct Answer
verified

Use this representation to answer the following questions. DNA template strand 5' 3' DNA complementary strand 3' 5' -Given the locally unwound double strand above, in which direction does the RNA polymerase move?

Correct Answer
verified

Correct Answer
verified