Deck 10: From Dna to Protein: Gene Expression

Question 1

MRSA is a variant of

A) Escherichia coli.
B) Staphylococcus aureus.
C) Bacillus anthracis.
D) Mycobacterium riggeti.
E) Mycobacterium roochi.

Answer 1

B

Question 2

During initiation,the sequence of DNA to which RNA polymerase binds most tightly is the

A) promoter.
B) poly C center.
C) poly A tail.
D) 5' cap.
E) minor groove.

Answer 2

promoter.

Question 3

Mapping studies have determined that within a group of mutants with the same growth requirements (i.e. ,the same overt phenotype),individual mutations are on different chromosomes.This indicates that

A) the same gene governs all the steps in a particular biological pathway.
B) different genes can govern different individual steps in the same biological pathway.
C) different genes govern the same step in a particular biological pathway.
D) all biological pathways are governed by different genes.
E) genes do not govern steps in biological pathways,but proteins do.

Answer 3

B

Question 4

The typical treatment for people with phenylketonuria is a diet low in phenylalanine.If one were to design a gene therapy for this disease,which would be the most promising approach?

A) Doing nothing.
B) Engineering a gene that codes for the enzyme that converts tyrosine to phenylalanine
C) Engineering a gene that codes for the enzyme that converts homogentistic acid to phenylalanine
D) Reducing the level of protein synthesis from a gene that codes for the enzyme that converts phenylalanine to tyrosine
E) Engineering a gene that codes for the enzyme that converts phenylalanine to tyrosine

Question 5

Which discovery caused the modification of the "one gene-one protein" hypothesis to the "one gene-one polypeptide" hypothesis?

A) Proteins made up of two or more chains
B) Splicing
C) Introns
D) Nonsense mutations
E) Garrod's inborn errors of metabolism

Question 6

In bacteria,_______ kind(s)of RNA polymerase catalyze(s)the synthesis of RNA from DNA.

A) one
B) three
C) four
D) five
E) six

Question 7

Tetracycline,but not penicillin,is able to kill MRSA because tetracycline

A) changes the shape of the bacterial cell walls.
B) blocks glycolysis.
C) inhibits protein synthesis.
D) degrades DNA.
E) blocks the input of nutrients.

Question 8

Which molecule(s)is/are not required for transcription?

A) A DNA template
B) RNA polymerase
C) A primer
D) Appropriate ribonucleoside triphosphates
E) All of the above are required.

Question 9

Which statement about the flow of genetic information is true?

A) Proteins encode information that is used to produce other proteins of the same amino acid sequence.
B) RNA encodes information that is translated into DNA,and DNA encodes information that is translated into proteins.
C) Proteins encode information that is translated into RNA,and RNA encodes information that is transcribed into DNA.
D) DNA encodes information that is translated into RNA,and RNA encodes information that is translated into proteins.
E) DNA encodes information that is translated into proteins and RNA.

Question 10

Use the following to answer questions :
Suppose that a wild-type bacterium can synthesize substance D,but various mutant strains cannot.We know that substance D is synthesized from substance X in a pathway that involves three intermediate substances (A,B,and C),but we do not know the order of the steps in the pathway.Below is a table of four different mutant strains that have been tested for their ability to grow on the various substances.The plus sign means that the strain can grow on that substance;the negative sign means that the strain cannot grow on that substance.
Suppose that another strain (strain 5)can grow on substance B but cannot grow on substance C.What can we infer from this observation?

A) Strain 5 cannot grow on substance A.
B) Strain 5 cannot grow on substance D.
C) Strain 5 has a defect in the enzyme that converts substance B to substance C.
D) Strain 5 has a defect in the enzyme that converts substance B to substance D.
E) Strain 5 has a defect in the enzyme that converts substance C to substance B.

Question 11

RNA polymerase is a

A) polysaccharide.
B) lipid.
C) protein.
D) nucleic acid.
E) carbohydrate/lipid mixture.

Question 12

What is the most likely reason that alkaptonuria is a recessive disease?

A) The mutant phenotype arises from a change in the protein's amino acid sequence.
B) More than half the typical amount of homogentisic acid oxidase is needed to break down the toxin by-product.
C) Having half the typical amount of homogentisic acid oxidase is sufficient to break down the toxin by-product.
D) Homogentisic acid oxidase occurs early in the metabolic pathway.
E) Homogentisic acid oxidase occurs late in the metabolic pathway.

Question 13

The "adapters" that allow translation of the four-letter nucleic acid language into the 20-letter protein language are called

A) aminoacyl tRNA synthetases.
B) transfer RNAs.
C) ribosomal RNAs.
D) messenger RNAs.
E) ribosomes.

Question 14

Use the following to answer questions :
Suppose that a wild-type bacterium can synthesize substance D,but various mutant strains cannot.We know that substance D is synthesized from substance X in a pathway that involves three intermediate substances (A,B,and C),but we do not know the order of the steps in the pathway.Below is a table of four different mutant strains that have been tested for their ability to grow on the various substances.The plus sign means that the strain can grow on that substance;the negative sign means that the strain cannot grow on that substance.
According to the data above,what is the most likely order of the pathway?

A) A,B,C,D
B) A,C,B,D
C) B,A,C,D
D) C,B,A,D
E) C,A,B,D

Question 15

Which type of molecule transfers information from mRNA to protein?

A) DNA
B) Polysaccharides
C) tRNA
D) Proteins
E) Lipids

Question 16

Which type of molecule is most involved in the transfer of genetic information from the nucleus to the cytoplasm?

A) DNA
B) mRNA
C) tRNA
D) Proteins
E) Lipids

Question 17

Transcription is the process by which

A) a DNA molecule is synthesized from an RNA template.
B) ribonucleoside triphosphates are assembled into an RNA molecule without a template.
C) an RNA molecule is synthesized from a DNA template.
D) a protein is synthesized with information from a messenger RNA.
E) a single-stranded DNA molecule is replicated.

Question 18

The _______ strand of DNA is transcribed to produce an RNA strand by DNA bases pairing with _______ bases of RNA.

A) coding;the same
B) coding;complementary
C) coding;reverse
D) template;the same
E) template;complementary

Question 19

Which statement about alkaptonuria is false?

A) Individuals with the disease have low levels of homogentistic acid.
B) Individuals with the disease often have dark or black urine.
C) The disease is due to a recessive allele at a single gene.
D) The disease is an example of Garrod's inborn errors of metabolism.
E) The disease arises from an improperly functioning enzyme.

Question 20

Which principle does the genetics of hemoglobin in humans illustrate?

A) Not all genes code for enzymes.
B) One gene codes for one enzyme.
C) All mutations of the same gene have the same phenotypic effect.
D) Not all genes code for polypeptides.
E) Proteins can code for DNA.

Question 21

Termination of transcription involves a

A) terminator sequence.
B) stop codon.
C) termiproteator.
D) hairline slip.
E) series of As.

Question 22

A transcription factor is _______ that assists transcription by binding to _______.

A) a protein;a ribosome
B) a protein;the promoter
C) DNA;a ribosome
D) DNA;the promoter
E) RNA;DNA

Question 23

You have carried out a process of nucleic acid hybridization with the DNA from a eukaryotic gene as the target and mRNA as the probe.You observe a region where the RNA and DNA pair,a middle region where the RNA and DNA do not pair,and a final region where the RNA and DNA pair.From this result,you can infer there is/are _______ exon(s)and _______ intron(s).

A) 1;0
B) 1;2
C) 2;1
D) 2;2
E) 3;1

Question 24

Promoters are made of

A) proteins.
B) carbohydrates.
C) lipids.
D) nucleic acids.
E) amino acids.

Question 25

Consensus sequences (short segments of DNA)appear in the boundaries between introns and exons of various genes.These sequences appear to be involved in

A) directing the polymerases to the appropriate place on the DNA for transcription to begin.
B) the splicing of introns out of the DNA.
C) allowing transcription to stop at the appropriate spot.
D) catalyzing the synthesis of a protein.
E) providing information to orient RNA polymerase.

Question 26

When eukaryotic DNA is hybridized with mRNA,the hybrid molecules contain loops of double-stranded DNA called

A) retroviruses.
B) introns.
C) exons.
D) transcripts.
E) puffs.

Question 27

If a template DNA strand has the base sequence 3-GTC…CCA-5,what would be the sequence of the corresponding mRNA? [Note: "…" represents an intervening sequence.]

A) 3'-GUC…CCA-5'
B) 5'-GUC…CCA-5'
C) 3'-CAG…GGU-5'
D) 5'-CAG…GGU-3'
E) 5'-CAG…GGT-3'

Question 28

Given the mRNA strand 5'-AUGCCU…CCA-3',what is the sequence of the template strand of DNA? [Note: "…" represents an intervening sequence.]

A) 5'-AUGCCU…CCA-3'
B) 5''-ATGCCT…CCA-3'
C) 3'-AUGCCU…CCA-5'
D) 3'-UACGGA…GGU-5'
E) 3'-TACGGA…GGT-5'

Question 29

Use the following to answer questions :
Suppose the DNA of a gene contains five motifs (A,B,C,D,and E)in that order.Motifs A,B,and D are located in introns,while motifs C and E are located in exons.
What is the order of the motifs in the mature mRNA transcribed from that sequence?

A) CE
B) ABD
C) BAD
D) ABDCE
E) ABCDE

Question 30

The direction of synthesis for a new mRNA molecule is _______ from a _______ template strand.

A) 5'-to-3';5'-to-3'
B) 5'-to-3';3'-to-5'
C) 3'-to-5';5'-to-3'
D) 3'-to-5';3'-to-5'
E) 5'-to-5';3'-to-3'

Question 31

In eukaryotes,exons are

A) spliced out of the original transcript.
B) spliced together from the original transcript.
C) spliced to introns to form the final transcript.
D) usually much larger than introns.
E) larger than the original coding region.

Question 32

If a 5'-to-3' strand of DNA has the sequence GTCTATGCATTA,what would be the sequence of the resulting transcribed RNA?

A) 5'-GUCUAUGCAUUA-3'
B) 5'-GTCTATGCATTA-3'
C) 5'-CAGATACGTAAT-3'
D) 5'-CAGAUACGUAAU-3'
E) 3F'-GUCUAUGCAUUA-5'

Question 33

Compared with DNA replication,transcription is _______ error prone because of differences in _______.

A) more;the number of copies made
B) less;the proofreading system
C) more;excision repair
D) less;the number of copies made
E) more;the proofreading system

Question 34

The transcription initiation site is located

A) within the promoter.
B) on RNA polymerase.
C) at splice sites.
D) in a ribosome.
E) at the consensus sequences.

Question 35

What two factors make errors in transcription less potentially harmful than errors in DNA replication?

A) The increased efficiency of proofreading repair in transcription and the large numbers of RNA sequences produced
B) The increased efficiency of proofreading repair in transcription and the reduced lifespan of RNA sequences
C) The reduced lifespan of RNA sequences and the large numbers of RNA sequences produced
D) The large numbers of RNA sequences produced and the fidelity function
E) The fidelity function and the increased efficiency of proofreading repair in transcription

Question 36

In a nucleic acid hybridization experiment performed to detect exons,the probe is

A) single-stranded DNA.
B) double-stranded DNA.
C) triple-stranded DNA.
D) single-stranded RNA.
E) double-stranded RNA.

Question 37

RNA polymerase uses the _______ DNA template to synthesize a _______ mRNA.

A) 5'-to-3';5'-to-3'
B) 3'-to-5';3'-to-5'
C) 5'-to-3';3'-to-5'
D) 3'-to-5';5'-to-3'
E) 5'-to-5';3'-to-3'

Question 38

Which statement about promoters is false?

A) Some promoters are more efficient than others at initiating transcription.
B) Various proteins can bind to the promoter.
C) Promoters provide information that orients RNA polymerase to the strand of the DNA it should use as a template.
D) A promoter is a DNA sequence.
E) Bacterial genes lack promoters.

Question 39

Use the following to answer questions :
Suppose the DNA of a gene contains five motifs (A,B,C,D,and E)in that order.Motifs A,B,and D are located in introns,while motifs C and E are located in exons.
What is the order of the motifs in the pre-mRNA transcribed from that sequence?

A) CE
B) ABD
C) BAD
D) ABDCE
E) ABCDE

Question 40

If a 5'-to-3' strand of DNA has the sequence GTCTATGCATTA,what is the template DNA strand that would be used for transcription?

A) 5'-GTCTATGCATTA-3'
B) 5'-CAGATACGTAAT-3'
C) 3'-GTCTATGCATTA-5'
D) 3'-CAGATACGTAAT-5'
E) 5'-GUCUAUGCAUUA-3'

Question 41

Which mutation is least likely to cause a frame shift?

A) One that removes 6 nucleotides from a sequence
B) One that adds 8 nucleotides to a sequence
C) One that removes 2 nucleotides from a sequence
D) One that adds 14 nucleotides to a sequence
E) One that adds 5 nucleotides to a sequence

Question 42

The three-dimensional structure of tRNA is maintained by

A) peptide bonds.
B) hydrogen bonds.
C) disulfide bridges.
D) phosphodiester bonds.
E) glycosidic linkages.

Question 43

Which statement about the 5' cap of mRNA is false?

A) It protects mRNA from being digested by enzymes.
B) It is added to the pre-mRNA during transcription.
C) It is a chemical modification of GTP.
D) It assists in transport of mRNA from the nucleus to the cytoplasm.
E) All of the above are true;none is false.

Question 44

The anticodon 3'-AUC-5' would pair with the codon

A) 5'-ATC-3'.
B) 5'-AUC-3'.
C) 5'-UAG-3'.
D) 5'-TAG-3'.
E) 5'-CAU-3'.

Question 45

Use the following to answer questions :
Suppose a gene has three exons,with 570 nucleotides in exon 1,420 in exon 2,and 810 in exon 3.
The protein translated from this gene is _______ amino acids long.

A) 190
B) 440
C) 600
D) 1,320
E) 1,800

Question 46

Suppose that a certain mRNA is transcribed at a normal rate in the nucleus,but it is found at very low levels in the cytoplasm.Which of the following would be the most plausible explanation for this phenomenon?

A) A defect in the addition of the poly A tail on the pre-mRNA
B) A defect in a spliceosome
C) A defect in nucleic acid hybridization
D) Overactive termination
E) A defect in the promoter

Question 47

The anticodon 3'-GCI-5'could not pair with

A) 5'-GCA-3'.
B) 5'-GCG-3'.
C) 5'-GCU-3'.
D) 5'-GCC-3'.
E) The anticodon could pair with all of the above.

Question 48

Which statement best illustrates the concept that the genetic code is redundant?

A) The codons CCU and CCC both code for the amino acid proline.
B) The codon CAG could code for two different amino acids.
C) The codons CUU and CCU code for different amino acids.
D) In some protists,UAG encodes for glutamine rather than functioning as a stop codon.
E) In nearly all organisms,UUU codes for phenylalanine.

Question 49

In order to examine which molecule is recognized by the protein synthesis machinery,Seymour Benzer

A) chemically converted the amino acid on a charged tRNA.
B) manipulated the anticodon of a charged tRNA.
C) manipulated the anticodon of an uncharged tRNA.
D) chemically changed the aminoacyl-tRNA synthetase.
E) charged a tRNA molecule with two different amino acids.

Question 50

UGU and UGC both code for cysteine.A change from UGU to UGC would thus be a(n)_______ mutation.

A) missense
B) nonsense
C) ambiguous
D) silent
E) frame-shift

Question 51

Imagine that a novel life form is found deep within Earth's crust.It uses DNA as an information storage molecule,and transcription and translation occur as in other life forms with one exception: a codon for this organism is just two bases in length.What is the maximum number of different amino acids that could be encoded from such a genetic code?

A) 8
B) 16
C) 24
D) 32
E) 64

Question 52

Which statement about the genetic code is true?

A) Eukaryotes,archaea,and bacteria each evolved the genetic code independently.
B) The common ancestor of eukaryotes and archaea evolved the genetic code independently from the one evolved by bacteria.
C) The common ancestor of eukaryotes and bacteria evolved the genetic code independently from the one evolved by archaea.
D) The common ancestor of archaea and bacteria evolved the genetic code independently from the one evolved by eukaryotes.
E) The genetic code evolved in the common ancestor of all known life.

Question 53

Which statement about tRNAs is false?

A) Any particular tRNA binds to one and only one amino acid.
B) tRNAs bind physically to mRNA.
C) The three-dimensional structure of tRNA results from hydrogen bonding between complementary bases.
D) tRNAs interact with ribosomes.
E) During elongation,the anticodon of an incoming tRNA first binds to the codon at the P site.

Question 54

Use the following to answer questions :
Suppose a gene has three exons,with 570 nucleotides in exon 1,420 in exon 2,and 810 in exon 3.
Now suppose there is a variant in which exon 2 is also spliced out from the mature mRNA.The protein translated from this genetic variant is _______ amino acids long.

A) 190
B) 460
C) 600
D) 1,320
E) 1,800

Question 55

Which finding would be the most plausible?

A) A pre-RNA strand is longer than the corresponding mature mRNA.
B) A pre-RNA strand is shorter than the corresponding mature mRNA.
C) The nucleotides of a pre-RNA strand are in a different order from those of the corresponding mature mRNA.
D) A mature mRNA strand contains more introns than the corresponding pre-RNA.
E) Introns scramble the order of genes.

Question 56

How many codons encode amino acids?

A) 20
B) 23
C) 45
D) 61
E) 64

Question 57

The three codons in the genetic code that do not specify amino acids are called

A) missense codons.
B) start codons.
C) stop codons.
D) promoters.
E) initiator codons.

Question 58

An mRNA molecule with 360 codons has _______ nucleotides.

A) 120
B) 180
C) 360
D) 1,080
E) 2,160

Question 59

Which change affects one and only one amino acid in a sequence?

A) A silent mutation
B) A deletion mutation
C) A frame-shift mutation
D) A nonsense mutation
E) A missense mutation

Question 60

The "wobble" phenomenon refers to a lack of specificity between the _______ end of the codon and the _______ end of the anticodon.

A) 5';3'
B) 5';5'
C) 5';2'
D) 3';5'
E) 3';3'

Question 61

Aminoacyl-tRNA synthases

A) are transcription factors.
B) are responsible for the wobble phenomenon.
C) charge tRNAs.
D) are responsible for the fidelity function.
E) bind tRNA to rRNA.

Question 62

Proteins are synthesized starting at the _______,in the _______ direction along the mRNA.

A) A site;3'-to-5'
B) A site;5'-to-3'
C) N terminus;3'-to-5'
D) C terminus;3'-to-5'
E) N terminus;5'-to-3'

Question 63

The addition of sugar residues to the protein after translation is called

A) glycation.
B) glycosylation.
C) phosphorylation.
D) proteolysis.
E) exonuclease digestion.

Question 64

What is a ribozyme?

A) Any component of the ribosome
B) The structure formed when multiple peptide chains are gathered together
C) Any RNA with catalytic ability
D) The structure formed when tRNAs are charged
E) Any RNA-DNA hybrid

Question 65

A tRNA that forms hydrogen bonds with all of the three bases of the codon will most likely be _______ by the ribosome,and this process will involve _______ subunit(s)of the ribosome.

A) accepted;the large
B) rejected;the small
C) rejected;the large
D) rejected;both
E) accepted;the small

Question 66

Suppose you take glycine tRNA and modify it so that the glycine is changed to valine.You then find that the amino acid sequence in the generated proteins does not change.This result would suggest that the protein synthesis machinery recognizes the ______,and is _______ with what was actually found.

A) amino acid;consistent
B) tRNA;inconsistent
C) mRNA;inconsistent
D) tRNA;consistent
E) amino acid;inconsistent

Question 67

A newly formed protein whose destination is the Golgi apparatus will likely contain

A) a protein release factor.
B) a polysome.
C) a signal sequence.
D) a spliceosome.
E) directing factors.

Question 68

Peptidyl transferase activity is due to the _______ component of the _______ subunit of the ribosome.

A) protein;large
B) protein;small
C) RNA;large
D) RNA;small
E) sugar;large

Question 69

After translation,the polypeptide chains of some proteins are cut by a process called

A) glycation.
B) glycosylation.
C) phosphorylation.
D) proteolysis.
E) exonuclease digestion.

Question 70

Sometimes an established antibiotic loses its effectiveness because of evolved changes in the amino acid sequence of the bacterial gene.This phenomenon is known as antibiotic _______.

Question 71

A polysome is

A) the structure formed when a polypeptide is glycosylated.
B) a signal sequence.
C) the structure formed when multiple peptide chains are gathered together.
D) a protein release factor.
E) the structure formed when multiple ribosomes are translating an mRNA molecule.

Question 72

Ribosomes are a collection of _______ that are needed for _______.

A) small proteins;translation
B) proteins and small RNAs;translation
C) proteins and tRNAs;transcription
D) proteins and mRNAs;translation
E) mRNAs and tRNAs;translation

Question 73

During translation initiation,the first site occupied by a charged tRNA is the _______ site.

A) A
B) N
C) E
D) T
E) P

Question 74

During translation,the formation of a peptide bond between an amino acid at the P site and an amino acid at the A site is catalyzed by

A) the large ribosomal subunit.
B) a specialized segment of DNA.
C) a specialized segment of RNA.
D) the initiation complex.
E) initiation factors.

Question 75

In eukaryotes,ribosomes become associated with endoplasmic reticulum membranes when a signal sequence

A) on the mRNA interacts with a receptor protein on the membrane.
B) on the ribosome interacts with a receptor protein on the membrane.
C) at the amino terminus of the protein being synthesized interacts with a receptor protein on the ribosome.
D) on the protein being synthesized interacts with a signal recognition particle and both bind to the endoplasmic reticulum.
E) on the mRNA passes through a pore in the membrane.

Question 76

In what order does a charged tRNA molecule move between the three sites on the ribosome?

A) A,E,P
B) P,E,A
C) E,P,A
D) P,A,E
E) A,P,E

Question 77

Stop codons terminate translation by

A) increasing peptidyl transferase activity.
B) binding a protein release factor,causing hydrolysis of the bond between the polypeptide chain and the tRNA.
C) binding a signal sequence,causing hydrolysis of the bond between the polypeptide chain and the tRNA.
D) interfering with the working of the ribosome,leading to the ribosome's secretion of protein release factors.
E) decreasing peptidyl transferase activity.

Question 78

In protein synthesis,the endoplasmic reticulum

A) is the site of mRNA attachment.
B) is the site where all ribosomes bind.
C) is the site of translation of membrane-bound and exported proteins.
D) produces tRNAs.
E) brings together mRNA and tRNA.

Question 79

Why do tetracyclines kill bacteria but not eukaryotic cells?

A) Bacterial and eukaryotic ribosomes differ in their specific proteins and RNAs.
B) Bacteria and eukaryotic tRNAs bind different amino acids.
C) Tetracyclines cannot enter the nucleus of eukaryotic cells.
D) Tetracyclines cannot enter the ER of eukaryotic cells.
E) Tetracyclines are destroyed by enzymes found only in eukaryotes.

Question 80

Which statement about methionine is false?

A) It is always the first amino acid in a new polypeptide chain in eukaryotes.
B) It is always the first amino acid in mature proteins in eukaryotes.
C) In a modified form,it is the first amino acid in a new polypeptide chain in bacteria.
D) Transfer RNAs that bind to start codons are charged with methionine.
E) It is encoded by the start codon.