Deck 13: Bacterial Genome Replication and Expression

Question 1

The process by which the base sequence of an RNA molecule is used to direct the synthesis of a protein is called

A)replication.
B)transcription.
C)reverse transcription.
D)translation.

Answer 1

D

Question 2

When a protein is synthesized,cis- or trans-splicing of that protein occurs

A)following translation.
B)between transcription and translation.
C)during transcription.
D)prior to transcription.

Answer 2

A

Question 3

If you wished to design an antimicrobial agent that prevented the formation of the 70S initiation complex in bacterial translation,which molecule should be specifically be targeted?

A)IF-3
B)mRNA
C)Peptidyl transferase
D)EF-1

Answer 3

A

Question 4

Some microbial proteins are spliced after translation in a reaction that results in removal of one or more internal intervening sequences called exteins.

Question 5

A complex consisting of a single mRNA molecule with several ribosomes is called a

A)polysome.
B)multisome.
C)maxisome.
D)proteosome.

Question 6

During translation elongation,which event happens last?

A)A tRNA carrying an amino acid binds to the A site.
B)A peptide bond forms.
C)A tRNA molecule translocates from the A site to the P site.
D)A tRNA molecule translocates from the P site to the E site.

Question 7

Proteins that recognize unfolded polypeptides and help them fold into their proper conformations are called ______________.

Question 8

During proteins are moved from the cytoplasm to the membrane or periplasmic space,while during proteins are moved from the cytoplasm to the external environment.

A)translocation; secretion
B)secretion; translocation
C)transcription; translation
D)translocation; translation
E)secretion; translation

Question 9

What is the minimum number of aminoacyl-tRNA synthetase enzymes needed to attach amino acids to all the various tRNA molecules?

A)20
B)61
C)64
D)As many as there are different tRNAs.

Question 10

This initiator tRNA of the bacterium Escherichia is a modified form of the initiator tRNA used by the yeast Saccharomyces.

Question 11

Which is true regarding translation in bacteria?

A)Translation begins with formation of the 30S initiation complex.
B)Translation ends when the Shine-Delgarno sequence is reached.
C)The 70S ribosome is composed of a 20S and 50S subunit.
D)All of the choices are correct.

Question 12

A bacterial cell that secretes proteins by types II and V systems is most likely Gram-negative.

Question 13

Signal recognition particles (SRPs)are associated with the Sec translocation system.

Question 14

The Tat and Sec pathways are protein translocation systems.

Question 15

What might be a reason for the accumulation of improperly folded protein complexes in the bacterial cell cytoplasm following translation?

A)A problem exists with the functioning of molecular chaperones.
B)The cell is synthesizing proteins too rapidly.
C)Polysomes are forming on the mRNA.
D)The proteins are being transcribed but not translated.

Question 16

DNA polymerase and aminoacyl-tRNA synthase are similar in that both have proofreading ability,but differ in the substrates that they act upon.

Question 17

Prior to secretion,Gram-negative bacterial proteins are translocated across one membrane while Gram-positive proteins are translocated across two membranes.

Question 18

The Sec system is used by

A)both Gram-positive and Gram-negative bacteria.
B)neither Gram-positive nor Gram-negative bacteria.
C)Gram-positive bacteria only.
D)Gram-negative bacteria only.

Question 19

Aminoacyl-tRNA synthetases catalyze covalent addition of __________ __________ to tRNAs.

Question 20

In __________,ribosomes can attach to the mRNA and begin translation even though transcription has not been completed.

A)prokaryotes
B)eukaryotes
C)fungi
D)protozoa and some plants

Question 21

In order to add a single amino acid to a growing polypeptide chain,a total of __________ molecules or ATP of GTP are utilized.

A)two
B)three
C)four
D)six

Question 22

Choose the description below that best matches the current model of RNA polymerase holoenzyme.

A)A core enzyme composed of five polypeptides bound by a transcription factor.
B)A core enzyme composed of five polypeptides bound by ribosomes.
C)A core enzyme composed of five sigma factors bound by a polypeptide chain.
D)An open complex or "bubble" formed by DNA,mRNA,and RNA polymerase.

Question 23

The energy needed for protein synthesis is provided by the hydrolysis of

A)ATP.
B)GTP.
C)UTP.
D)ATP and GTP.
E)ATP and UTP.

Question 24

Ribosomes consist of __________ separate subunits that come together as part of the initiation process and dissociate immediately after termination.

A)two
B)three
C)four
D)five

Question 25

All prokaryotes initiate the synthesis of proteins with formylmethionine.

Question 26

Which of the following is not a termination codon?

A)AUG
B)UAA
C)UAG
D)UGA

Question 27

The stop codons are translated codons; that is,they specify amino acids to be inserted into the last position of a growing polypeptide chain.

Question 28

Two amino acids that are found in some proteins due to exceptions in the universal genetic code are

A)pyrrolysine and selenocysteine.
B)lysine and selenocysteine.
C)pyrrolysine and cysteine.
D)lysine and cysteine.

Question 29

How many different termination codons are used in translation?

A)One
B)Two
C)Three
D)Four

Question 30

During transcription elongation,how many pyrophosphate molecules are produced from the incorporation of 20 ribonucleoside monophosphates?

A)20
B)40
C)60
D)5

Question 31

The genetic code is translated in groups of __________ bases.

A)two
B)three
C)four
D)five

Question 32

________ molecules deliver amino acids to ribosomes during translation.

A)Messenger RNA (mRNA)
B)Transfer RNA (tRNA)
C)Ribosomal RNA (rRNA)
D)Heterogeneous nuclear RNA (hnRNA)

Question 33

Messenger RNA molecules that direct the synthesis of more than one polypeptide are said to be __________.

Question 34

What would be the most likely outcome if the genetic code was not degenerate?

A)The effect of some mutations would increase.
B)The effect of some mutations would decrease.
C)The mutation rate would remain the same.
D)The number of stop codons would increase.

Question 35

Which of the following is the initiator codon?

A)AUG
B)UAA
C)UAG
D)UGA

Question 36

Which set of codons terminate transcription in most organisms?

A)UGA,UAG,UAA
B)AGU,UAG,UAA
C)ACT,TAC,ATT
D)TGA,TAG,TAA

Question 37

The portion of the tRNA molecule that binds to the codon on the mRNA is called the

A)c-codon.
B)anticodon.
C)complementary codon.
D)paracodon.

Question 38

The genetic code is said to be __________ because more than one codon will specify a particular amino acid.

A)ambiguous
B)degenerate
C)multiplicative
D)repetitious

Question 39

The __________ reaction sequentially links adjacent amino acids into the growing polypeptide chain.

A)dipeptidation
B)transpeptidation
C)peptidation
D)propeptidation

Question 40

How many DNA triplets encode 60 amino acids?

A)60
B)180
C)20
D)30

Question 41

The transcribed and translated region of a gene is the __________ region.

A)leader
B)promoter
C)coding
D)trailer

Question 42

When RNA polymerase catalyzes the addition of a nucleotide to a growing mRNA chain,a byproduct of this reaction is

A)phosphate.
B)pyrophosphate.
C)orthophosphate.
D)water.

Question 43

Which of the following is common to both factor-dependent and factor-independent transcription termination?

A)Both types of termination occur following a pause by the polymerase.
B)Both types of termination are associated with rho termination factor.
C)Both types of termination involve NusA protein.
D)None of the above are correct.

Question 44

If the DNA of a new discovered organism exhibits genes that are arranged as operons and lacks intron sequences,the hypothesis that this organism is bacterial rather than mammalian would be supported by the evidence.

Question 45

The process by which the base sequence of all or a portion of a DNA molecule is used to direct the synthesis of an RNA molecule is called

A)replication.
B)transcription.
C)reverse transcription.
D)translation.

Question 46

Key sequences exist within promoters,which vary somewhat among various promoters but are sufficiently constant that they can be represented by a sequence of bases most often found at each position.These representations are called __________ sequences.

A)convergence
B)idealized
C)consensus
D)common

Question 47

Messenger RNA molecules have a nontranslated sequence called the __________ ,which is located downstream of the termination codon.

Question 48

Which of the following is a correct comparison between RNA polymerase holoenzyme that functions in transcription and the primase enzyme that functions in DNA replication?

A)Both enzymes synthesize RNA.
B)Both enzymes are bound by sigma factor.
C)Both enzymes synthesize DNA.
D)Both enzymes are composed of RNA.

Question 49

Which modification of the terminator region of a gene would specifically prevent rho-independent termination?

A)Change in the adenine-rich sequence of nucleotides of the terminator region.
B)Change in the adenine-thymine sequence of the Pribnow box.
C)Change in the sequence that encodes the mRNA leader.
D)Change in the rut binding site.

Question 50

A bacterial __________ is the nontranscribed region of the DNA to which RNA polymerase binds in order to initiate transcription.

A)operon
B)operator
C)promoter
D)initiator

Question 51

The unexpressed regions of split genes are called

A)exons.
B)endons.
C)introns.
D)codons.

Question 52

Modify the following statement to make it correct: Ribozymes are ribonucleosomes used by bacteria and eukaryotic cells to modify DNA.

A)Ribozymes are ribonucleases used by bacteria and eukaryotic cells to modify RNA.
B)Ribozymes are ribonucleosomes used by bacteria and eukaryotic cells to modify RNA.
C)Ribozymes are ribonucleases used by bacteria and eukaryotic cells to modify DNA.
D)Ribozymes are ribonucleosomes used only by eukaryotic cells to modify RNA.

Question 53

In Escherichia coli,if $\sigma$ ⁷⁰ is not bound to RNA polymerase core enzyme,active transcription of the gene is not occurring.

Question 54

If the product of a functional gene is not a protein,what other product(s)might be encoded by the gene?

A)tRNA and rRNA
B)tRNA and mRNA
C)mRNA and rRNA
D)mRNA,tRNA,and RNA

Question 55

On mRNA molecules,a nontranslated sequence called the ___________ usually precedes the initiation codon.

Question 56

The region at which the RNA polymerase binds is the __________ region.

A)leader
B)promoter
C)coding
D)trailer

Question 57

Which of the following is in the coding region of a gene?

A)Promoter
B)Leader
C)Trailer
D)None of the choices are correct.

Question 58

Which statement defends the concept that the term "gene" is better defined as a nucleotide sequence that encodes for one or more functional products rather than encoding for one or more functional proteins?

A)Products of genes include ribonucleotides as well as proteins.
B)Intron sequences in DNA do not encode proteins.
C)The genetic code is redundant,therefore the same codon may be encoded by different DNA triplets.
D)Genes in bacteria are organized as operons that can lead to several protein products.

Question 59

The Pribnow box of

A)is centered approximately 35 bp upstream of the start site of transcription.
B)is centered between 7 and 13 bp upstream of the start codon.
C)is centered approximately 10 bp upstream of the start site of transcription.
D)is located at the site of addition of poly (A)in eukaryotic mRNAs.
E)coli

Question 60

Postranscriptional modification to remove introns is needed for the bacterial RNA that has codon,rather than anticodon,sequences.

Question 61

Which enzyme is a topoisomerase?

A)DNA gyrase
B)DNA ligase
C)DNA polymerase I
D)DNA polymerase III

Question 62

Choose the correct order of proteins that function in the initiation,elongation,and termination stages of DNA replication.

A)DnaA,DNA polymerase III,DNA polymerase I,DNA ligase
B)DnaA,DNA polymerase I,DNA polymerase III,DNA ligase
C)DNA polymerase III,DNA polymerase I,DNA ligase,DnaA
D)DNA polymerase I,DnaA,DNA polymerase III,DNA ligase

Question 63

The transcribed,but not translated,sequence that is immediately upstream of the region that encodes the functional product is called the __________ region.

A)leader
B)promoter
C)coding
D)trailer

Question 64

The noncoding sequences located between the start codon and the stop codon in interrupted genes are called introns.

Question 65

In terms of relatedness to a specific cellular process,which protein does not belong with the others?

A)RNA polymerase holoenzyme
B)DNA polymerase holoenzyme
C)Ribonuclease
D)DNA ligase

Question 66

While examining the sequence of nucleotides in the replicon region of bacterial DNA,you note an abundance of adenine and thymine base pairs.This leads you to conclude that this particular section of the DNA must be the

A)oriC site.
B)Pribnow box.
C)Shine-Delgarno sequence.
D)ter site.

Question 67

The coding sequence in the DNA of __________ is normally continuous; that is,it is not interrupted by noncoding sequences.

A)prokaryotes
B)plants
C)mammals
D)most insects

Question 68

The strand of DNA for a particular gene that is copied by the RNA polymerase to form mRNA is called the __________ strand.

A)leading
B)template
C)transcription
D)copy

Question 69

Bacterial chromosomes,unlike eukaryotic chromosomes,often consist of a single replicon.

Question 70

When a DNA molecule is replicated,the daughter molecules contain one strand of parental DNA and one strand of newly synthesized DNA; this is called __________ replication.

A)hemiconservative
B)conservative
C)semiconservative
D)dispersive

Question 71

Bacteria with DNA described as having "hairpin ends with inverted repeats" must not have circular chromosomes.

Question 72

A consensus sequence in the untranslated leader sequence of a prokaryotic mRNA,which serves as a ribosome binding site is called the _____ - _____ sequence.

Question 73

Each chromosome has one or more __________ site(s)where replication begins.

A)promoter
B)replicon
C)origin
D)bifurcate

Question 74

The genetic information in DNA is divided into units called

A)proteins.
B)genes.
C)genotype.
D)phenotype.

Question 75

A scientist wishes to develop an antimicrobial agent that specifically targets replication elongation in Escherichia coli without interfering with proteins that catalyze other replication processes.Which of the following experimental designs is most appropriate for the scientist to explore?

A)Develop a molecule that interferes with the DNA-binding ability of DNA polymerase III core enzyme.
B)Modify an existing antibiotic to act as a competitive inhibitor of DNA polymerase I.
C)Design a drug that modifies the structural configuration of DNA at the oriC locus.
D)Create a novel protein that acts as a competitive inhibitor of the DNA ligase binding site.

Question 76

The Y-shaped part of the DNA molecule where the actual replication process occurs is called the replication __________.

A)tongue
B)fork
C)junction
D)splice

Question 77

Which of the following is a region of DNA at the end of a linear chromosome?

A)Telomere
B)Primer
C)Intron
D)Exon

Question 78

During DNA replication,deoxyribonucleosides are added to the 5' end of Okazaki fragments and to the 3' end of the leading strand.

Question 79

DNA replication is a complex process,and,as a result,the frequency of error is quite high.

Question 80

Catenanes are interlocked chromosomes that form during the termination stage of DNA replication.