Chapter 17

Which one of the following structures, if missing, would usually prevent translation from starting? A. exon B. 5′ cap C. AUG codon D. poly-A tail

C. AUG codon

What determines which base is to be added to an RNA strand during transcription? A. Base pairing between the two DNA strands B. The order of the chemical groups in the backbone of the RNA molecule C. Base pairing between the DNA template strand and the RNA nucleotides D. The previous base

C. Base pairing between the DNA template strand and the RNA nucleotides

If a DNA sequence is altered from TAGCTGA to TAGTGA, what kind of mutation has occurred? A. Addition. B. Both addition and deletion. C. Deletion. D. None.

C. Deletion.

Which of the following statements correctly describes the function of a signal peptide? A. It signals the initiation of transcription. B. It terminates translation of messenger RNA. C. It helps target a protein to the ER. D. It directs an mRNA molecule into the cisternal space of the ER.

C. It helps target a protein to the ER.

Which of the following statements correctly describes the effect a nonsense mutation would have on a gene? A. It changes an amino acid in the encoded protein. B. It has no effect on the amino acid sequence of the encoded protein. C. It introduces a premature stop codon into the mRNA. D. It alters the reading frame of the mRNA. 10 points

C. It introduces a premature stop codon into the mRNA.

The following question refers to this table of codons. What amino acid sequence will be generated, based on the following mRNA codon sequence? 5-AUG-UCU-UCG-UUA-UCC-UUG-3 A. Met-Ser-Leu-Ser-Leu-Ser B. Met-Glu-Arg-Arg-Glu-Leu C. Met-Ser-Ser-Leu-Ser-Leu D. Met-Arg-Glu-Arg-Glu-Arg

C. Met-Ser-Ser-Leu-Ser-Leu

Which mutation(s) would not change the remainder of the reading frame of a gene sequence that follows the mutation(s)? A. One addition and two deletion mutations. B. One deletion mutation. C. One addition and one deletion mutation. D. One addition mutation.

C. One addition and one deletion mutation.

What is the process called that converts the genetic information stored in DNA to an RNA copy? A. Translation B. Replication C. Transcription D. Translocation

C. Transcription

Refer to the figure. Which of the triplets below is a possible anticodon for a tRNA that transports proline to a ribosome? The following question refers to this table of codons. A. 3-UUC-5 B. 3-CCC-5 C. 3-CCG-5 D. 3-GGC-5

D. 3-GGC-5

The following question refers to this table of codons. Which of the following sequences of nucleotides are possible in the template strand of DNA that would code for the polypeptide sequence Phe-Leu-Ile-Val? A. 3-AAA-GAA-TAA-CAA-5 B. 5-AUG-CTG-CAG-TAT-3 C. 5-TTG-CTA-CAG-TAG-3 D. 3-AAA-AAT-ATA-ACA-5

A. 3-AAA-GAA-TAA-CAA-5

Use the following information to answer the question. 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. Which of the following anticodons in the first tRNA to bind will complement this mRNA? A. 3-GGC-5 B. 5-GGC-3 C. 3-UGC-5 D. 5-UGC-3

A. 3-GGC-5

Use this model of a eukaryotic transcript to answer the following question. E = exon and I = intron5' UTR E1 I1 E2 I2 E3 I3 E4 UTR 3' Which components of the previous molecule will also be found in mRNA in the cytosol? A. 5' UTR E1 E2 E3 E4 UTR 3' B. 5' E1 I1 E2 I2 E3 I3 E4 3' C. 5' E1 E2 E3 E4 3' D. 5' UTR I1 I2 I3 UTR 3'

A. 5' UTR E1 E2 E3 E4 UTR 3'

The genetic code is essentially the same for all organisms. From this, one can logically assume which of the following statements to be true? A. A gene from an organism can theoretically be expressed by any other organism. B. DNA was the first genetic material. C. The same codons in different organisms translate into different amino acids. D. Different organisms have different types of amino acids.

A. A gene from an organism can theoretically be expressed by any other organism.

Which of the following statements about mutations is false? A. A knock-out mutation results in a total absence of the mutated protein. B. Addition and deletion mutations disrupt the primary structure of proteins. C. A deletion mutation results in the loss of a base in the DNA sequence. D. An addition mutation results in an added base in the DNA sequence.

A. A knock-out mutation results in a total absence of the mutated protein.

Transcription begins at a promoter. What is a promoter? A. A site in DNA that recruits the RNA Polymerase B. A site found on the RNA polymerase C. Part of the RNA molecule itself D. The same as a start codon

A. A site in DNA that recruits the RNA Polymerase

Which of the following processes occurs when termination of translation takes place? A. A stop codon is reached. B. The poly-A tail is reached. C. The 5 cap is reached. D. The end of the mRNA molecule is reached.

A. A stop codon is reached.

If a mutated DNA sequence produces a protein that differs in one central amino acid from the normal protein, which of the following kinds of mutations could have occurred? A. An addition mutation and a deletion mutation. B. A deletion mutation. C. An addition mutation D. None.

A. An addition mutation and a deletion mutation.

What is the function of the release factor during translation in eukaryotes? A. It binds to the stop codon in the A site in place of a tRNA. B. It releases the amino acid from its tRNA to allow the amino acid to form a peptide bond. C. It releases the ribosome from the ER to allow polypeptides into the cytosol. D. It supplies a source of energy for termination of translation.

A. It binds to the stop codon in the A site in place of a tRNA.

What happens to RNA polymerase II after it has completed transcription of a gene? A. It is free to bind to another promoter and begin transcription. B. It begins transcribing the next gene on the chromosome. C. It joins with another RNA polymerase to carry out transcription. D. It is degraded.

A. It is free to bind to another promoter and begin transcription.

Once researchers identified DNA as the molecule responsible for transmitting heritable traits, they asked how information was transferred from the DNA in the nucleus to the site of protein synthesis in the cytoplasm. Which of the following statements correctly describes the mechanism of information transfer in eukaryotes that accomplishes this task? A. Messenger RNA is transcribed from a single gene and transfers information from the DNA in the nucleus to the cytoplasm, where protein synthesis takes place. B. Histone proteins in the chromosomes transfer information from the nucleus to the ribosome, where protein synthesis takes place. C. DNA from a single gene is replicated and transferred to the cytoplasm, where it serves as a template for protein synthesis. D. Transfer RNA takes information from DNA directly to a ribosome, where protein synthesis takes place.

A. Messenger RNA is transcribed from a single gene and transfers information from the DNA in the nucleus to the cytoplasm, where protein synthesis takes place.

Which of the following processes is an example of a post-translational modification? A. Phosphorylation B. Elongation C. Initiation D. Peptide bond formation

A. Phosphorylation

What name is given to the process in which pre-mRNA is edited into mRNA? A. RNA processing B. gene expression C. polypeptide formation D. transcription E. translation

A. RNA processing

Where does translation take place? A. Ribosome B. Golgi apparatus C. Nucleus D. Endoplasmic reticulum

A. Ribosome

Which of the following steps occurs last in the initiation phase of translation? A. The large ribosomal subunit joins the complex. B. A peptide bond is formed between two adjacent amino acids. C. An aminoacyl tRNA binds to the start codon. D. The small subunit of the ribosome binds to the 5' cap on the mRNA.

A. The large ribosomal subunit joins the complex.

What enzyme catalyzes the attachment of an amino acid to tRNA? A. aminoacyl-tRNA synthetase B. rubisco C. dextrinase D. argininosuccinate lyase E. nuclease

A. aminoacyl-tRNA synthetase

Translation occurs in the _____. A. cytoplasm B. lysosome C. nucleus D. Golgi apparatus E. nucleoplasm

A. cytoplasm

According to the central dogma, what is the intermediate molecule involved in the flow of information in a cell that should go in the blank? DNA → ________ → Proteins A. mRNA B. rRNA C. mtDNA D. tRNA

A. mRNA

Which of the following molecules are required for the process of translation? A. mRNA, tRNA, and rRNA B. mRNA, DNA, and rRNA C. mRNA, tRNA, and DNA D. mRNA, tRNA, DNA, and rRNA

A. mRNA, tRNA, and rRNA

Use the following information to answer the question. 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. Which of the following dipeptides will form from this mRNA? A. proline-threonine B. glycine-cysteine C. alanine-alanine D. cysteine-alanine

A. proline-threonine

Spliceosomes are composed of _____. A. small RNAs and proteins B. polymerases and ligases C. introns and exons D. the RNA transcript and protein

A. small RNAs and proteins

Once a peptide bond has been formed between the amino acid attached to the tRNA in the P site and the amino acid associated with the tRNA in the A site, what process occurs next? A. translocation B. reading of the next codon of mRNA C. initiation D. The codon-anticodon hydrogen bonds holding the tRNA in the A site are broken.

A. translocation

Use the scheme to answer the question. A ⟶enzymeA B ⟶ enzymeB C There is a simple metabolic pathway. According to Beadle and Tatum's hypothesis, how many genes are necessary for this pathway? A. 1 B. 2 C. 3 D. It cannot be determined from the pathway.

B. 2

The direction of synthesis of an RNA transcript is _____. A. 1' —> 5' B. 5' —> 3' C. 1' —> 3' D. 3' —> 5' E. 2' —> 4'

B. 5' —> 3'

Which of these is a tRNA? A. A B. B C. C D. D E. E

B. B

In the diagram below, the two blue strands represent _____. A. RNA B. DNA C. transcription factors D. RNA polymerase E. the promoter

B. DNA

Which of these correctly illustrates the pairing of DNA and RNA nucleotides? A.GTTACG CAATCG B. GTTACG CAAUGC C. GTTACG GTTACG D. GTTACG ACCGTA E. GTTACG UAACAU

B. GTTACG CAAUGC

Which of the following processes correctly describes alternative RNA splicing? A. It is a mechanism for increasing the rate of translation. B. It can allow the production of proteins of different sizes and functions from a single mRNA. C. It can allow the production of similar proteins from different RNAs. D. It increases the rate of transcription.

B. It can allow the production of proteins of different sizes and functions from a single mRNA.

Which of the following processes occurs during transcription? A. DNA is replicated B. RNA is synthesized C. proteins are synthesized D. mRNA attaches to ribosomes

B. RNA is synthesized

In eukaryotes, there are several different types of RNA polymerase. Which type is involved in transcription of mRNA for a globin protein? A. primase B. RNA polymerase II C. RNA polymerase III D. RNA polymerase I

B. RNA polymerase II

Which of the following statements best describes the termination of transcription in prokaryotes? A. Once transcription has initiated, RNA polymerase transcribes until it reaches the end of the chromosome. B. RNA polymerase transcribes through the terminator sequence, causing the polymerase to separate from the DNA and release the transcript. C. RNA polymerase transcribes through the polyadenylation signal, causing proteins to associate with the transcript and cut it free from the polymerase. D. RNA polymerase transcribes through a stop codon, causing the polymerase to stop advancing through the gene and release the mRNA.

B. RNA polymerase transcribes through the terminator sequence, causing the polymerase to separate from the DNA and release the transcript.

Which of the following statements best describes the promoter of a protein-coding gene? A. The promoter is part of the RNA molecule itself. B. The promoter is a nontranscribed region of a gene. C. The promoter is a site found on RNA polymerase. D. The promoter is a site at which only RNA polymerase will bind.

B. The promoter is a nontranscribed region of a gene.

A particular triplet of bases in the coding strand of DNA is AAA. The anticodon on the tRNA that binds this mRNA codon is _____. A. TTT B. UUU C. UUA D. AAA

B. UUU

Which of the following statements is the most current description of a gene? A. a unit of heredity that causes formation of a phenotypic characteristic B. a DNA sequence that is expressed to form a functional product: either RNA or polypeptide C. a DNA subunit that codes for a single complete protein D. a discrete unit of hereditary information that consists of a sequence of amino acids

B. a DNA sequence that is expressed to form a functional product: either RNA or polypeptide

During RNA processing a(n) _____ is added to the 3' end of the RNA. A. 3' untranslated region B. a long string of adenine nucleotides C. 5' untranslated region D. coding segment E. modified guanine nucleotide

B. a long string of adenine nucleotides

The RNA segments joined to one another by spliceosomes are _____. A. caps B. exons C. snRNPs D. tails E. introns

B. exons

Which of the following molecular structures contain codons? A. a protein B. mRNA C. rRNA D. tRNA

B. mRNA

How does the primary transcript in the nucleus of a eukaryotic cell compare to the functional mRNA? A. the primary transcript is the same size as the mRNA B. the primary transcript is larger than the mRNA C. the primary transcript is smaller than the mRNA D. both the primary transcript and mRNA contain introns

B. the primary transcript is larger than the mRNA

A particular triplet of bases in the template strand of DNA is 5-AGT-3. What would be the corresponding codon for the mRNA that is transcribed? A. 3-ACU-5 B. 3-UGA-5 C. 3-UCA-5 D. 5-TCA-3

C. 3-UCA-5

Use the figure to answer the question. The figure represents tRNA that recognizes and binds a particular amino acid (in this instance, phenylalanine). Which codon on the mRNA strand codes for this amino acid? A. 3-GUG-5 B. 5-UGG-3 C. 5-UUC-3 D. 5-GUA-3

C. 5-UUC-3

Which of the following processes occurs in eukaryotic gene expression? A. mRNA, tRNA, and rRNA are translated. B.RNA polymerase binds to the terminator sequence. C. A cap is added to the 5′ end of the mRNA. D. RNA polymerase requires tRNA to elongate the molecule.

C. A cap is added to the 5′ end of the mRNA.

During the elongation phase of translation, which site in the ribosome represents the location where a codon is being read? A. E site B. P site C. A site D. the large ribosomal subunit

C. A site

At which site do new aminoacyl tRNAs enter the ribosome during elongation? A. B-site B. P-site C. A-site D. E-site

C. A-site

What would be the consequence of a mutation in a bacterial cell that produces a defective aminoacyl-tRNA synthetase that attaches a lysine instead of the normal phenylalanine to tRNAs with the anticodon AAA? A. None of the proteins in the cell will contain phenylalanine. B. The ribosome will skip a codon every time a UUU is encountered. C. Proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU. D. The cell will compensate for the defect by attaching phenylalanine to tRNAs with lysine-specifying anticodons.

C. Proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU.

Which one of the following statements about RNA processing is correct? A. A primary transcript is often much shorter than the final RNA molecule that leaves the nucleus. B. Exons are cut out before mRNA leaves the nucleus. C. Ribozymes may function in RNA splicing. D. RNA splicing can be catalyzed by tRNA.

C. Ribozymes may function in RNA splicing.

What is meant by translocation? A. The two ribosomal subunits are joined in a complex. B. The completed polypeptide is released from the ribosome. C. The ribosome slides one codon down the mRNA. D. The polypeptide chain grows by one amino acid.

C. The ribosome slides one codon down the mRNA.

If the sequence ATGCATGTCAATTGA were mutated such that a base were inserted after the first G and the third T were deleted, how many amino acids would be changed in the mutant protein? A. One. B. Three. C. Two. D. None.

C. Two.

A single base substitution mutation is likely to have a less deleterious effect when the base change exhibits which of the following results? A. a stop codon B. an amino acid substitution at the active site of an enzyme C. a codon that specifies the same amino acid as the original codon D. an amino acid substitution that alters the tertiary structure of the protein

C. a codon that specifies the same amino acid as the original codon

Accuracy in the translation of mRNA into the primary structure of a polypeptide depends on specificity in the _____. A. binding of the anticodon to small subunit of the ribosome B. attachment of amino acids to rRNAs C. binding of the anticodon to the codon and the attachment of amino acids to tRNAs D. binding of ribosomes to mRNA

C. binding of the anticodon to the codon and the attachment of amino acids to tRNAs

What is the name of the process shown in the diagram? A. initiation (of transcription) B. RNA processing C. initiation (of translation) D. elongation E. termination (of translation)

C. initiation (of translation)

Transcription in eukaryotes requires which of the following molecules in addition to RNA polymerase? A. anticodons B. ribosomes and tRNA C. several transcription factors D. aminoacyl-tRNA synthetase

C. several transcription factors

Which of the following characteristics is directly related to the coding of a single amino acid during the process of translation? A. the base sequence of the tRNA B. the amino acetyl tRNA synthase C. the three-base sequence of mRNA D. the complementarity of DNA and RNA

C. the three-base sequence of mRNA

Which of the following processes occurs in prokaryotes but not in eukaryotes? A. post-transcriptional splicing B. translation in the absence of a ribosome C. transcription and translation occur simultaneously D. gene splicing

C. transcription and translation occur simultaneously

The following question refers to this table of codons. Refer to the figure. Which of the triplets below is a possible anticodon for a tRNA that transports proline to a ribosome? A. 3-UUC-5 B. 3-CCC-5 C. 3-CCG-5 D. 3-GGC-5

D. 3-GGC-5

Rank the following one-base point mutations with respect to their likelihood of affecting the structure of the corresponding polypeptide (from most likely to least likely).1. insertion mutation deep within an intron2. substitution mutation at the third position of a codon in an exon3. substitution mutation at the second position of a codon in an exon4. deletion mutation within the first exon of the gene A. 3, 1, 4, 2 B. 2, 1, 4, 3 C. 1, 2, 3, 4 D. 4, 3, 2, 1

D. 4, 3, 2, 1

The tRNA anticodon, GAC, is complementary to the mRNA codon with the sequence _____. A. CAG B. CTG C. GAC D. CUG E. TCG

D. CUG

Codons are three-base sequences in mRNA that specify the addition of a single amino acid to the growing protein chain during translation. How do eukaryotic codons and prokaryotic codons compare? A. Prokaryotic codons usually contain different bases than those of eukaryotes. B. Prokaryotic codons usually specify different amino acids than those of eukaryotes. C. The translation of codons is mediated by tRNAs in eukaryotes, but translation requires no intermediate molecules such as tRNAs in prokaryotes. D. Codons are a nearly universal language among all organisms.

D. Codons are a nearly universal language among all organisms.

Which of the following terms best describes the relationship between the newly synthesized RNA molecule and the DNA template strand? A. Identical B. Permanently base-paired C. Covalently bound D. Complementary

D. Complementary

Which of the following statements best describes the significance of the TATA box in the promoters of eukaryotes? A. It sets the reading frame of the mRNA during translation. B. It is the recognition site for ribosomal binding during transcription. C. It is the recognition site for ribosomal binding during translation. D. It is the recognition site for the binding of a specific transcription factor.

D. It is the recognition site for the binding of a specific transcription factor.

DNA does not store the information to synthesize which of the following? A. Proteins B. DNA C. Messenger RNA D. Organelles

D. Organelles

The initiator tRNA attaches at the ribosome's _____ site. A. A B. translocation C. E D. P E. Q

D. P

In the diagram below, the gray unit represents _____. A. RNA B. DNA C. transcription factors D. RNA polymerase E. the promoter

D. RNA polymerase

In bacteria, there are 61 mRNA codons that specify an amino acid, but only 45 tRNAs. Which of the following statements explains this fact? A. The DNA codes for all 61 tRNAs, but some are then destroyed. B. Many codons are never used, so the tRNAs that recognize them are dispensable. C. Some tRNAs have anticodons that recognize four or more different codons. D. The rules for base pairing between the third base of a codon and tRNA are flexible.

D. The rules for base pairing between the third base of a codon and tRNA are flexible.

Which of the following statements is true about protein synthesis in prokaryotes? A. Prokaryotic cells have complicated mechanisms for targeting proteins to the appropriate cellular organelles. B. Extensive RNA processing is required before prokaryotic transcripts can be translated. C. Unlike eukaryotes, prokaryotes require no initiation or elongation factors. D. Translation can begin while transcription is still in progress.

D. Translation can begin while transcription is still in progress.

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? A. a substitution of the first nucleotide of a GGG codon B. a substitution of the third nucleotide in an ACC codon C. a deletion of a codon D. a deletion of two nucleotides

D. a deletion of two nucleotides

Post-translational modifications of proteins may include which of the following processes? A. removal of introns B. addition of a poly-A tail C. addition of a 5 cap D. addition of carbohydrates to form a glycoprotein

D. addition of carbohydrates to form a glycoprotein

Use the scheme to answer the question. A ⟶enzymeA B ⟶enzymeB C Refer to the metabolic pathway illustrated. 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 medium supplemented with which of the following nutrient(s)? A. nutrient A only B. nutrient C only C. nutrients A and C D. either nutrient B or C

D. either nutrient B or C

Use the figure to answer the question. What type of bonding is responsible for maintaining the shape of the tRNA molecule shown in the figure? A. peptide bonding between amino acids B. van der Waals interactions between hydrogen atoms C. ionic bonding between phosphates D. hydrogen bonding between base pairs

D. hydrogen bonding between base pairs

RNA processing converts the RNA transcript into _____. A. a protein B. DNA C. a eukaryotic cell D. mRNA E. a polypeptide

D. mRNA

Which nucleic acid is translated to make a protein? A. DNA B. rRNA C. tRNA D. mRNA

D. mRNA

How does the primary transcript in a prokaryotic cell compare to the functional mRNA? A. the primary transcript is smaller than the mRNA B. the primary transcript and the mRNA both contain introns C. the primary transcript is larger than the mRNA D. the primary transcript is the same size as the mRNA

D. the primary transcript is the same size as the mRNA

Which of the following processes is the first event to take place in translation in eukaryotes? A. base pairing of activated methionine-tRNA to AUG of the messenger RNA B. binding of the larger ribosomal subunit to smaller ribosomal subunits C. the ribosome reaches a stop codon D. the small subunit of the ribosome recognizes and attaches to the 5′ cap of mRNA

D. the small subunit of the ribosome recognizes and attaches to the 5′ cap of mRNA

What name is given to the process in which a strand of DNA is used as a template for the manufacture of a strand of pre-mRNA? A. RNA processing B. gene expression C. polypeptide formation D. transcription E. translation

D. transcription

Polypeptides are assembled from _____. A. hexoses B. glycerol C. nucleotides D. proteins E. amino acids

E. amino acids

During RNA processing a(n) _____ is added to the 5' end of the RNA. A. 3' untranslated region B. a long string of adenine nucleotides C. 5' untranslated region D. coding segment E. modified guanine nucleotide

E. modified guanine nucleotide

In the diagram below, the green unit represents _____. A. RNA B. DNA C. transcription factors D. RNA polymerase E. the promoter

E. the promoter

What name is given to the process in which the information encoded in a strand of mRNA is used to construct a protein? A. RNA processing B. gene expression C. polypeptide formation D. transcription E. translation

E. translation

True or false. A tRNA with an anticodon complementary to the stop codon catalyzes the reaction by which translation is terminated. True False

False

True or false? A codon is a group of three bases that can specify more than one amino acid.

False