Question 1

Which of the following is not True of RNA processing?

Accepted Answer

A) Exons are cut out before mRNA leaves the nucleus. 
B) Nucleotides may be added at both ends of the RNA. 
C) Ribozymes may function in RNA splicing. 
D) RNA splicing can be catalyzed by spliceosomes. 
E) A primary transcript is often much longer than the final RNA molecule that leaves the nucleus. 
A) Exons are cut out before mRNA leaves the nucleus. 
B) Nucleotides may be added at both ends of the RNA. 
C) Ribozymes may function in RNA splicing. 
D) RNA splicing can be catalyzed by spliceosomes. 
E) A primary transcript is often much longer than the final RNA molecule that leaves the nucleus.

Question 2

A mutation in which of the following parts of a gene is likely to be most damaging to a cell?

Accepted Answer

A) intron 
B) exon 
C) 5' UTR 
D) 3' UTR 
E) All would be equally damaging. 
A) intron 
B) exon 
C) 5' UTR 
D) 3' UTR 
E) All would be equally damaging.

Question 3

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. 
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 4

When does translation begin in prokaryotic cells?

Accepted Answer

A) after a transcription initiation complex has been formed 
B) as soon as transcription has begun 
C) after the 5' caps are converted to mRNA 
D) once the pre-mRNA has been converted to mRNA 
E) as soon as the DNA introns are removed from the template 
A) after a transcription initiation complex has been formed 
B) as soon as transcription has begun 
C) after the 5' caps are converted to mRNA 
D) once the pre-mRNA has been converted to mRNA 
E) as soon as the DNA introns are removed from the template

Question 5

Each eukaryotic mRNA, even after post-transcriptional modification, includes 5' and 3' UTRs. Which are these?

Accepted Answer

A) the cap and tail at each end of the mRNA 
B) the untranslated regions at either end of the coding sequence 
C) the U attachment sites for the tRNAs 
D) the U translation sites that signal the beginning of translation 
E) the U - A pairs that are found in high frequency at the ends 
A) the cap and tail at each end of the mRNA 
B) the untranslated regions at either end of the coding sequence 
C) the U attachment sites for the tRNAs 
D) the U translation sites that signal the beginning of translation 
E) the U - A pairs that are found in high frequency at the ends

Question 6

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. 
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.

Question 7

If proteins were composed of only 12 different kinds of amino acids, what would be the smallest possible codon size in a genetic system with four different nucleotides?

Accepted Answer

A) 1 
B) 2 
C) 3 
D) 4 
E) 12 
A) 1 
B) 2 
C) 3 
D) 4 
E) 12

Question 8

Which point 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 
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 9

A mutant bacterial cell has a defective aminoacyl synthetase that attaches a lysine to tRNAs with the anticodon AAA instead of a phenylalanine. The consequence of this for the cell will be that

Accepted Answer

A) none of the proteins in the cell will contain phenylalanine. 
B) proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU. 
C) the cell will compensate for the defect by attaching phenylalanine to tRNAs with lysine-specifying anticodons. 
D) the ribosome will skip a codon every time a UUU is encountered. 
E) None of the above will occur; the cell will recognize the error and destroy the tRNA. 
A) none of the proteins in the cell will contain phenylalanine. 
B) proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU. 
C) the cell will compensate for the defect by attaching phenylalanine to tRNAs with lysine-specifying anticodons. 
D) the ribosome will skip a codon every time a UUU is encountered. 
E) None of the above will occur; the cell will recognize the error and destroy the tRNA.

Question 10

As a ribosome translocates along an mRNA molecule by one codon, which of the following occurs?

Accepted Answer

A) The tRNA that was in the A site moves into the P site. 
B) The tRNA that was in the P site moves into the A site. 
C) The tRNA that was in the A site moves to the E site and is released. 
D) The tRNA that was in the A site departs from the ribosome via a tunnel. 
E) The polypeptide enters the E site. 
A) The tRNA that was in the A site moves into the P site. 
B) The tRNA that was in the P site moves into the A site. 
C) The tRNA that was in the A site moves to the E site and is released. 
D) The tRNA that was in the A site departs from the ribosome via a tunnel. 
E) The polypeptide enters the E site.

Question 11

Which of the following statements best describes the termination of transcription in prokaryotes?

Accepted Answer

A) RNA polymerase transcribes through the polyadenylation signal, causing proteins to associate with the transcript and cut it free from the polymerase. 
B) RNA polymerase transcribes through the terminator sequence, causing the polymerase to fall off the DNA and release the transcript. 
C) RNA polymerase transcribes through an intron, and the snRNPs cause the polymerase to let go of the transcript. 
D) Once transcription has initiated, RNA polymerase transcribes until it reaches the end of the chromosome. 
E) RNA polymerase transcribes through a stop codon, causing the polymerase to stop advancing through the gene and release the mRNA. 
A) RNA polymerase transcribes through the polyadenylation signal, causing proteins to associate with the transcript and cut it free from the polymerase. 
B) RNA polymerase transcribes through the terminator sequence, causing the polymerase to fall off the DNA and release the transcript. 
C) RNA polymerase transcribes through an intron, and the snRNPs cause the polymerase to let go of the transcript. 
D) Once transcription has initiated, RNA polymerase transcribes until it reaches the end of the chromosome. 
E) RNA polymerase transcribes through a stop codon, causing the polymerase to stop advancing through the gene and release the mRNA.

Question 12

Which of the following help(s)to stabilize mRNA by inhibiting its degradation?

Accepted Answer

A) TATA box 
B) spliceosomes 
C) 5' cap and poly (
A) tail 
D) introns 
E) RNA polymerase 
A) TATA box 
B) spliceosomes 
C) 5' cap and poly (
A) tail 
D) introns 
E) RNA polymerase

Question 13

An experimenter has altered the 3' end of the tRNA corresponding to the amino acid methionine in such a way as to remove the 3' AC. Which of the following hypotheses describes the most likely result?

Accepted Answer

A) tRNA will not form a cloverleaf. 
B) The nearby stem end will pair improperly. 
C) The amino acid methionine will not bind. 
D) The anticodon will not bind with the mRNA codon. 
E) The aminoacylsynthetase will not be formed. 
A) tRNA will not form a cloverleaf. 
B) The nearby stem end will pair improperly. 
C) The amino acid methionine will not bind. 
D) The anticodon will not bind with the mRNA codon. 
E) The aminoacylsynthetase will not be formed.

Question 14

Which of these is the function of a poly (A)signal sequence?

Accepted Answer

A) It adds the poly (
A) tail to the 3' end of the mRNA. 
B) It codes for a sequence in eukaryotic transcripts that signals enzymatic cleavage ~10-35 nucleotides away. 
C) It allows the 3' end of the mRNA to attach to the ribosome. 
D) It is a sequence that codes for the hydrolysis of the RNA polymerase. 
E) It adds a 7-methylguanosine cap to the 3' end of the mRNA. 
A) It adds the poly (
A) tail to the 3' end of the mRNA. 
B) It codes for a sequence in eukaryotic transcripts that signals enzymatic cleavage ~10-35 nucleotides away. 
C) It allows the 3' end of the mRNA to attach to the ribosome. 
D) It is a sequence that codes for the hydrolysis of the RNA polymerase. 
E) It adds a 7-methylguanosine cap to the 3' end of the mRNA.

Question 15

What are the coding segments of a stretch of eukaryotic DNA called?

Accepted Answer

A) introns 
B) exons 
C) codons 
D) replicons 
E) transposons 
A) introns 
B) exons 
C) codons 
D) replicons 
E) transposons

Question 16

RNA polymerase moves in which direction along the DNA?

Accepted Answer

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

Question 17

The following questions refer to Figure 17.1, a simple metabolic pathway:

-If A, B, and C are all required for growth, a strain that is mutant for the gene encoding enzyme A would be able to grow on which of the following media?

Accepted Answer

A) minimal medium 
B) minimal medium supplemented with nutrient "A" only 
C) minimal medium supplemented with nutrient "B" only 
D) minimal medium supplemented with nutrient "C" only 
E) minimal medium supplemented with nutrients "A" and "C" 
A) minimal medium 
B) minimal medium supplemented with nutrient "A" only 
C) minimal medium supplemented with nutrient "B" only 
D) minimal medium supplemented with nutrient "C" only 
E) minimal medium supplemented with nutrients "A" and "C"

Question 18

Figure 17.4  
-The tRNA shown in Figure 17.4 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. 
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 19

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. 
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 20

The anticodon of a particular tRNA molecule is

Accepted Answer

A) complementary to the corresponding mRNA codon. 
B) complementary to the corresponding triplet in rRNA. 
C) the part of tRNA that bonds to a specific amino acid. 
D) changeable, depending on the amino acid that attaches to the tRNA. 
E) catalytic, making the tRNA a ribozyme. 
A) complementary to the corresponding mRNA codon. 
B) complementary to the corresponding triplet in rRNA. 
C) the part of tRNA that bonds to a specific amino acid. 
D) changeable, depending on the amino acid that attaches to the tRNA. 
E) catalytic, making the tRNA a ribozyme.

Exam 17: From Gene to Protein

Which of the following is not True of RNA processing?

A mutation in which of the following parts of a gene is likely to be most damaging to a cell?

A frameshift mutation could result from

When does translation begin in prokaryotic cells?

Each eukaryotic mRNA, even after post-transcriptional modification, includes 5' and 3' UTRs. Which are these?

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?

If proteins were composed of only 12 different kinds of amino acids, what would be the smallest possible codon size in a genetic system with four different nucleotides?

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

A mutant bacterial cell has a defective aminoacyl synthetase that attaches a lysine to tRNAs with the anticodon AAA instead of a phenylalanine. The consequence of this for the cell will be that

As a ribosome translocates along an mRNA molecule by one codon, which of the following occurs?

Which of the following statements best describes the termination of transcription in prokaryotes?

Which of the following help(s)to stabilize mRNA by inhibiting its degradation?

An experimenter has altered the 3' end of the tRNA corresponding to the amino acid methionine in such a way as to remove the 3' AC. Which of the following hypotheses describes the most likely result?

Which of these is the function of a poly (A)signal sequence?

What are the coding segments of a stretch of eukaryotic DNA called?

RNA polymerase moves in which direction along the DNA?

The following questions refer to Figure 17.1, a simple metabolic pathway: -If A, B, and C are all required for growth, a strain that is mutant for the gene encoding enzyme A would be able to grow on which of the following media?

Figure 17.4 -The tRNA shown in Figure 17.4 has its 3' end projecting beyond its 5' end. What will occur at this 3' end?

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

The anticodon of a particular tRNA molecule is

Introduction: Themes in the Study of Life

The Chemical Context of Life

Water and the Fitness of the Environment

Carbon and the Molecular Diversity of Life

The Structure and Function of Large Biological Molecules

A Tour of the Cell

Membrane Structure and Function

An Introduction to Metabolism

Cellular Respiration: Harvesting Chemical Energy

Photosynthesis

Cell Communication

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

Control of Gene Expression

Viruses

Biotechnology

Genomes and Their Evolution

Descent With Modification: a Darwinian View of Life

The Evolution of Populations

The Origin of Species

The History of Life on Earth

Phylogeny and the Tree of Life

Bacteria and Archaea

Protists

Plant Diversity I: How Plants Colonized Land

Plant Diversity Ii: the Evolution of Seed Plants

Fungi

An Introduction to Animal Diversity

Invertebrates

Vertebrates

Plant Structure, Growth, and Development

Transport in Vascular Plants

Soil and Plant Nutrition

Angiosperm Reproduction and Biotechnology

Plant Responses to Internal and External Signals

Basic Principles of Animal Form and Function

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Osmoregulation and Excretion

Hormones and the Endocrine System

Animal Reproduction

Animal Development

Neurons, Synapses, and Signaling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behavior

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems

Conservation Biology and Restoration Ecology

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