Deck 16: Transcription and Translation

Question 1

What is the function of the group of amino acids on the RNA polymerase,called the rudder?

A)It provides the energy required for formation of phosphodiester bonds in the elongating RNA molecule.
B)It helps unwind and open the DNA molecule.
C)It moves template and non-template strands of DNA through channels inside the enzyme.
D)It helps sigma bind to the RNA polymerase molecule.

Answer 1

C

Question 2

Which of the following does not occur in post-transcriptional modifications occurring in eukaryotic mRNAs?

A)addition of a poly (A)tail
B)addition of a methyl-guanosine cap
C)removal of introns
D)RNA polymerase termination

Answer 2

D

Question 3

Figure 16.1

The enzyme complex associated with DNA in the figure is _____.

A)helicase
B)DNA polymerase
C)RNA polymerase
D)topoisomerase

Answer 3

C

Question 4

Eukaryotes have three nuclear RNA polymerases.The primary function of RNA polymerase II is _____.

A)transcription of only rRNA-coding genes
B)transcription of only tRNA-coding genes
C)transcription of both rRNA- and tRNA-coding genes
D)transcription of protein-coding genes

Question 5

Put the following events of transcription in chronological order.
1)Sigma binds to the promoter region.
2)The double helix of DNA is unwound,breaking hydrogen bonds between complementary strands.
3)Sigma binds to RNA polymerase.
4)Sigma is released.
5)Transcription begins.

A)2,3,4,5
B)2,3,1,4,5
C)3,1,2,5,4
D)3,2,1,4,5

Question 6

Codons are three-base sequences that specify the addition of a single amino acid.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.

Question 7

As scientists were unraveling the mysteries associated with transcription and translation,they discovered there was not a one-to-one correspondence between nucleotide sequence of a gene and base sequence of the mRNA it codes for.They proposed the genes-in-pieces hypothesis.How can the genes-in-pieces hypothesis be explained?

A)Introns are noncoding segments of DNA that are present in the initial transcript,but are removed by splicing.
B)Introns are noncoding segments of DNA that are not read or transcribed by RNA polymerase II.
C)Exons are noncoding segments of DNA that are not read or transcribed by RNA polymerase II.
D)Exons are noncoding segments of DNA that are present in the initial transcript,but are removed by splicing.

Question 8

David Pribnow studied the base sequences of promoters in bacteria and bacterial viruses.He found two conserved regions in these promoters (the -10 box and the -35 box).What is the function of these two regions of the promoter?

A)They signal the initiation site.
B)They bind the sigma subunit that is associated with RNA polymerase.
C)They attach the correct nucleotide triphosphate to the template DNA strand.
D)They separate the two DNA strands.

Question 9

Alpha-amanitin is a toxin produced by the death cap mushroom.It blocks the synthesis of mRNA.What effect would it have on health of the organism that ate death cap mushrooms?

A)It would block DNA synthesis.
B)It would tie up Mg²⁺ and through this action,inhibit glycolysis.
C)It would denature existing proteins.
D)It would cause death.

Question 10

Which molecule or reaction supplies the energy for polymerization of nucleotides in the process of transcription?

A)the interaction between RNA polymerase and the promoter
B)the phosphate bonds in the nucleotide triphosphates that serve as substrates
C)the energy released when hydrogen bonds are broken as the DNA molecule is unwound
D)ATP only

Question 11

During elongation,RNA polymerase has three prominent channels,or grooves.These channels provide sites for all of the following,except _____.

A)a site for the double-stranded DNA molecule
B)a site for the entry of ribonucleoside triphosphates
C)a site for the exit of the diphosphates removed from the nucleotide triphosphates
D)a site for the growing RNA strand

Question 12

How are RNA hairpin turns related to termination?

A)The turns are formed from complementary base pairing and cause separation of the RNA transcript and RNA polymerase.
B)A three-base repeat signals a stop sequence,and the RNA transcript is released.
C)Release factors bind to sites on the hairpin turn,causing release of the RNA transcript.
D)The hairpin turn prevents more nucleoside triphosphates from entering the active site of the enzymes,effectively shutting off the process of polymerization.

Question 13

A primary transcript in the nucleus of a eukaryotic cell is _____ the functional mRNA,while a primary transcript in a prokaryotic cell is _____ the functional mRNA.

A)the same size as;the same size as
B)larger than;the same size as
C)larger than;smaller than
D)the same size as;larger than

Question 14

Death cap mushrooms produce a substance called alpha-amanitin.Alpha-amanitin efficiently blocks synthesis of mRNA,but not of tRNA or rRNA in eukaryotic organisms.How is that possible?

A)Alpha-amanitin efficiently interferes with the action of RNA polymerase I,but not RNA polymerase II or III.
B)Alpha-amanitin efficiently interferes with RNA polymerase III,but not RNA polymerase I and II.
C)Alpha-amanitin efficiently blocks the action of one or more basic transcription factors.
D)Alpha-amanitin efficiently interferes with the action of RNA polymerase II,but not RNA polymerase I or III.

Question 15

Figure 16.2.

Refer to Figure 16.2.The mRNA is smaller than the length of the DNA that codes for it because _____.

A)the regulatory regions (introns)of the gene are not transcribed
B)post-transcriptional modification removes the introns
C)post-transcriptional modification removes the exons
D)bases are added to the tail of the primary transcript

Question 16

What molecule in the spliceosome lowers the activation energy so intron removal reactions can occur?

A)RNA polymerase
B)ribozymes
C)proteins of the spliceosome
D)autocatalysis by introns

Question 17

If RNA polymerase is missing _____ then transcription initiation would not occur but elongation could.

A)amino acids
B)mRNA
C)sigma
D)the holoenzyme

Question 18

Which of the following processes is central to the initiation of transcription?

A)binding of sigma to the promoter region
B)formation of a phosphodiester bond in the elongating RNA strand
C)binding of DNA polymerase to the promoter region
D)formation of a DNA primer

Question 19

Which of the following is part of a DNA molecule?

A)sigma
B)the holoenzyme
C)initiation factors
D)promoters

Question 20

The TATA box of the eukaryotic promoter is analogous to which structure of the prokaryotic promoter?

A)sigma
B)the -10 box
C)the -35 box
D)the site of initiation

Question 21

The mutation resulting in sickle cell anemia changes one base pair of DNA so it is an example of a _____.

A)point mutation
B)frameshift mutation
C)silent mutation
D)missense mutation

Question 22

How does termination of translation take place?

A)The end of the mRNA molecule is reached.
B)A stop codon is reached.
C)The 5' cap is reached.
D)The poly A tail is reached.

Question 23

Figure 16.3.

Refer to Figure 16.3.What is the function of the AGU on the loop of the tRNA?

A)It attaches to the amino acid.
B)It base pairs with the codon of mRNA.
C)It stabilizes the tRNA-amino acid complex.
D)It is the active site of this ribozyme.

Question 24

Which of the following is not one of the steps in initiation of translation?

A)binding of the large ribosomal subunit to the small ribosomal subunit
B)binding of tRNA carrying formyl methionine to the start codon and small ribosomal subunit
C)recognition and binding of mRNA by the small ribosomal subunit
D)formation of a polypeptide bond

Question 25

The ribosome-binding site of prokaryotes is also known as _____.

A)the TATA box
B)the promoter
C)the Shine-Dalgarno sequence
D)the Pribnow box

Question 26

Once a peptide 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,which process on the list 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.

Question 27

There are 61 codons that each specify the addition of a specific amino acid,and three stop codons for which there is no corresponding amino acid.However,there are only about 40 tRNA molecules,representing 40 anticodons.How is that possible?

A)Only about 40 of the recognized 61 codons are present in mRNA.
B)An anticodon forms hydrogen bonds with the codon;it must match the first two bases of the codon,but is less specific with respect to the third base.
C)There are tRNAs that can bind one of two related amino acids.
D)Only 20 of the codons are active-one for each amino acid.

Question 28

Ribosomes can attach to prokaryotic messenger RNA _____.

A)once post-transcriptional modification is complete
B)before transcription is complete
C)once replication is complete
D)once the primary transcript has been released from RNA polymerase

Question 29

A mutation that results in premature termination of translation _____.

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 mutation

Question 30

Which one of the following,if missing,would prevent transcription from starting?

A)exon
B)5' cap
C)AUG codon
D)poly A tail

Question 31

Which of the following occurs in prokaryotes,but not eukaryotes?

A)post-transcriptional splicing
B)concurrent transcription and translation
C)translation in the absence of a ribosome
D)gene regulation

Question 32

If the DNA code for a particular amino acid is AGT,then the anticodon on the tRNA would be _____.

A)AGT
B)TCA
C)UCA
D)AGU

Question 33

Figure 16.3.

Refer to Figure 16.3.What is the function of the ACC sequence at the 3' end?

A)It attaches to the amino acid.
B)It base pairs with the codon of mRNA.
C)It stabilizes the tRNA-amino acid complex.
D)It is the active site of this ribozyme.

Question 34

Put the following events of elongation in prokaryotic translation in chronological order.
1)Binding of mRNA with small ribosomal subunit
2)Recognition of initiation codon
3)Complementary base pairing between initiator codon and anticodon of initiator tRNA
4)Base pairing of the mRNA codon following the initiator codon with its complementary tRNA
5)Attachment of the large subunit

A)1,2,3,4,5
B)2,1,4,3,5
C)5,4,3,2,1
D)1,2,3,5,4

Question 35

There should be a strong positive correlation between the rate of protein synthesis and _____.

A)the quantity of DNA polymerase
B)the quantity of RNA polymerase
C)the size of mRNA
D)the number of ribosomes

Question 36

Post-translational modifications include all of the following except _____.

A)removal of introns
B)formation of hydrogen bonds among carbonyl and amino groups of the polypeptide backbone
C)formation of covalent bonds between cysteine residues of the amino acid side chains
D)addition of carbohydrates to form a glycoprotein

Question 37

What molecule/feature ensures that the correct amino acid is added with reading of a specific codon during translation?

A)the anticodon of a properly formed aminoacyl tRNA
B)the methyl-guanosine cap of a properly modified mRNA
C)the poly (A)tail of a properly modified mRNA
D)the twisting number of a properly supercoiled DNA

Question 38

Figure 16.4.

Refer to Figure 16.4.During elongation,which site in the ribosome represents the location where a codon is being read?

A)E site
B)P site
C)A site
D)small subunit