Chapter 4/7

Front 1

The functional unit of genetic information is the

A) nucleotide.B) gene.C) chromosome.D) protein.

Back 1

B) gene.

Front 2

2) Which of the following statements is TRUE concerning mRNA?A) mRNA has a very short half-life.B) mRNA has complex secondary structure.C) mRNA is catalytic.D) mRNA is the product of translation.

Back 2

A) mRNA has a very short half-life.

Front 3

3) DNA-binding proteins interact predominantly within which portion of a double-stranded DNA helix?A) major grooveB) minor grooveC) 3' endD) supercoil

Back 3

A) major groove

Front 4

AT-rich DNA will denature/meltA) at a higher temperature than GC-rich DNA.B) at a lower temperature than GC-rich DNA.C) usually at the same temperature as GC-rich DNA, with some minor variations.D) in accordance with the animal or plant from which it was taken.

Back 4

B) at a lower temperature than GC-rich DNA.

Front 5

Supercoiling is important for DNA structure, becauseA) it holds together the antiparallel strands of DNA in the double helix.B) it provides energy for transcription.C) it condenses the DNA so that it can fit inside the cell.D) it prevents RNA from pairing with DNA in the double helix.

Back 5

it condenses the DNA so that it can fit inside the cell.

Front 6

Many pharmaceutical drugs specifically inhibit transcription in Bacteria but not Archaea orEukarya. Why would drugs that inhibit transcription only affect Bacteria and not Archaea even though they are both prokaryotes?A) Archaea and Eukarya have very similar ribosomes that are different than bacterial ribosomes.B) Bacteria lack a nucleus.C) Archaea lack operons.D) Archaea and Eukarya have very similar RNA polymerases that are different than bacterial RNA polymerases.

Back 6

D) Archaea and Eukarya have very similar RNA polymerases that are different than bacterialRNA polymerases.

Front 7

How are plasmids different than chromosomes?A) Plasmids are always small, linear pieces of DNA.B) Plasmids are composed of single-stranded DNA.C) Plasmids contain genes that are NOT essential for cellular growth and replication.D) Plasmids carry unimportant genes that are of little significance for the ecology and metabolism of an organism.

Back 7

Plasmids contain genes that are NOT essential for cellular growth and replication.

Front 8

Genes that encoded for polymerases, gyrases, ribosomal proteins, and other proteins essentialto replication, transcription, and translation are present onA) chromosomes.B) plasmids.C) chromosomes and plasmids.D) neither chromosomes nor plasmids.

Back 8

chromosomes.

Front 9

The precursor of each new nucleotide in a strand of DNA is aA) deoxynucleoside 5'-diphosphate.B) deoxynucleoside 3'-diphosphate.C) deoxynucleoside 5'-triphosphate.D) deoxynucleoside 3'-triphosphate.

Back 9

deoxynucleoside 5'-triphosphate.

Front 10

DNA replication always proceeds in only one direction because the ________ of theincoming nucleotide is attached to the free ________ of the growing DNA strand.A) 5'-phosphate / 3'-hydroxylB) 3'-phosphate / 5'-hydroxylC) 5'-deoxyribose / 3'-baseD) 3'-base / 5'-deoxyribose

Back 10

5'-phosphate / 3'-hydroxyl

Front 11

Which of the following is formed on the lagging strand during DNA synthesis?A) DNA secondary structuresB) Okazaki fragmentsC) RNA polymeraseD) replisomes

Back 11

B) Okazaki fragments

Front 12

The template for RNA polymerase is ________, and the new RNA chain is ________ to thetemplate.A) an independent RNA segment / parallel and identicalB) DNA / antiparallel and complementaryC) an independent RNA segment / antiparallel and complementaryD) DNA / parallel and identical

Back 12

DNA / antiparallel and complementary

Front 13

In the process of transcription, promoters are specific sequences of ________ that arerecognized by ________.A) DNA / DNA polymeraseB) RNA / DNA polymeraseC) DNA / sigma factorsD) RNA / ribosomes

Back 13

DNA / sigma factors

Front 14

An example of correct nucleotide pairing isA) T and U.B) G and U.C) A and T.D) C and U.

Back 14

G and U.

Front 15

Stop codons are also called ________ codons.A) nonsenseB) release factorC) degeneracyD) conversion

Back 15

nonsense

Front 16

Transfer RNA moleculesA) function to transfer ribonucleotides to RNA polymerase during transcription.B) function to transfer the correct amino acids to the ribosome during translation.C) contain codons that bind to ribosomes during translation.D) are only present in the nucleus or eukaryotes.

Back 16

function to transfer the correct amino acids to the ribosome during translation.

Front 17

tRNA is released from the ribosome at the ________ site.

Back 17

E

Front 18

Which statement is TRUE regarding protein synthesis?A) Ribosomal proteins catalyze peptide bond formation in the growing polypeptide chain.B) The 23S rRNA catalyzes peptide bond formation in the growing polypeptide chain.C) Transfer RNAs catalyze peptide bond formation in the growing polypeptide chain.D) Messenger RNA catalyzes peptide bond formation in the growing polypeptide chain.

Back 18

The 23S rRNA catalyzes peptide bond formation in the growing polypeptide chain.

Front 19

The Tat system is involved inA) protein synthesis.B) transcriptional initiation.C) protein folding.D) protein secretion.

Back 19

protein secretion.

Front 20

In all cells, genes are composed ofA) nucleic acids.B) mRNA.C) proteins.D) chaperones.

Back 20

nucleic acids.

Front 21

Which of the following is an example of one codon?A) CATTB) GCCATTC) CAGD) CCGUAA

Back 21

C) CAG

Front 22

22) In all cells a gene encodes forA) a protein (via mRNA).B) a tRNA.C) an rRNA.D) a protein, tRNA, or rRNA depending on the specific gene.

Back 22

D) a protein, tRNA, or rRNA depending on the specific gene.

Front 23

Which of the following is NOT correct regarding DNA and RNA synthesis?A) The overall direction of chain growth is from the 5' to 3' end.B) Both processes require an RNA primer to begin.C) The template strand is antiparallel to the newly synthesized strand.D) DNA is the template for both DNA and RNA synthesis.

Back 23

Both processes require an RNA primer to begin.

Front 24

Termination of RNA synthesis is ultimately determined byA) exhaustion of RNA polymerase activity.B) special protein factors.C) terminases.D) specific nucleotide sequences on the template strand.

Back 24

specific nucleotide sequences on the template strand.

Front 25

GTP provides energy forA) transcription.B) translation.C) DNA replication.D) protein folding.

Back 25

translation.

Front 26

Transcription of chaperonins is greatly accelerated when a cell is stressed byA) excessive osmotic pressure.B) extremes in pH value.C) lack of oxygen.D) excessive heat.

Back 26

D) excessive heat.

Front 27

The flow of biological information begins withA) DNA replication.B) RNA transcription.C) mRNA translation.D) transcriptional regulation.

Back 27

DNA replication.

Front 28

28) DNA participates in protein synthesis throughA) cyclic messengers.B) direct pairing with amino acids.C) an RNA intermediate.D) protein folding.

Back 28

an RNA intermediate.

Front 29

The two strands of the DNA double helix are held together byA) 5' to 3' attraction.B) hydrogen bonds between nucleotide bases.C) codons.D) peptide bonds between nucleotide bases.

Back 29

hydrogen bonds between nucleotide bases.

Front 30

In Bacteria, a chromosome can be distinguished from a plasmid, because a chromosome is agenetic element thatA) is circular.B) is linear.C) encodes for essential functional genes.D) replicates via a bidirectional fork.

Back 30

encodes for essential functional genes.

Front 31

Transposable elements areA) segments of DNA that move from one site to another.B) transcribed genes.C) segments of RNA that are involved in transposing DNA into proteins.D) proteins that aid in the secretion of enzymes out of the cell.

Back 31

segments of DNA that move from one site to another.

Front 32

In complementary base pairing of DNA, adenine pairs with ________ (or ________ in RNA)and cytosine always pairs with ________.A) guanine / uracil / thymineB) uracil / thymine / guanineC) thymine / guanine / uracilD) thymine / uracil / guanine

Back 32

thymine / uracil / guanine

Front 33

The function of the DNA polymerase is to catalyzeA) the addition of deoxynucleotides.B) the formation of RNA primers.C) the addition of ribonucleotides.D) hydrogen bonding between complementary base pairs.

Back 33

the addition of deoxynucleotides.

Front 34

DNA replication is started with a(n) ________, which, in most cases, in vivo is a short stretchof ________.A) promoter / DNAB) mRNA / RNAC) primer / RNAD) ribosome-binding sequence / DNA

Back 34

primer / RNA

Front 35

The function of RNA polymerase is toA) catalyze the formation of phosphodiester bonds between deoxyribonucleotids.B) catalyze the formation of phosphodiester bonds between ribonucleotides.C) cleave mRNA to remove introns.D) activate tRNAs.

Back 35

catalyze the formation of phosphodiester bonds between ribonucleotides.

Front 36

Polycistronic transcription units are common inA) Archaea.B) Bacteria.C) Eukarya.D) both Archaea and Bacteria.

Back 36

both Archaea and Bacteria.

Front 37

An operon is a useful genetic element, because itA) encourages the binding of RNA polymerase.B) allows coordinated expression of multiple related genes in prokaryotes.C) translates DNA sequence into amino acid sequence.D) encourages the binding of ribosomes in the correct location.

Back 37

B) allows coordinated expression of multiple related genes in prokaryotes.

Front 38

Plasmids often encode for proteinsA) involved in translation.B) required for cellular growth.C) that confer resistance to antibiotics.D) involved in DNA replication.

Back 38

that confer resistance to antibiotics.

Front 39

The codon on the ________ matches with the anticodon on the ________ to direct theaddition of the correct amino acid to the growing polypeptide chain.A) mRNA / tRNAB) tRNA / mRNAC) DNA / mRNAD) tRNA / rRNA

Back 39

A) mRNA / tRNA

Front 40

40) The structure and function of a protein are determined by its ________ sequence.A) nucleotideB) amino acidC) ribonucleotideD) translocation

Back 40

amino acid

Front 41

You experimentally change the DNA sequence directly upstream of a start codon of anoperon in E. coli to investigate the function of this region of DNA. Analysis reveals that after the change the same amount of mRNA is made from the operon, but there are very few proteins made from the operon. What is the most likely function of the DNA sequence that you changed? A) The DNA sequence likely functions as a ribosome-binding site.B) The DNA sequence likely functions as a promoter.C) The DNA sequence likely functions as a termination sequence.D) The DNA sequence likely functions as in transcriptional regulation.

Back 41

The DNA sequence likely functions as a ribosome-binding site.

Front 42

In ________ several ribosomes can simultaneously translate a single mRNA molecule in acomplex called a(n) ________.A) prokaryotes / polysomeB) eukaryotes / polysomeC) prokaryotes / initiation complexD) eukaryotes / splicing complex

Back 42

A) prokaryotes / polysome

Front 43

You are studying a protein in Salmonella typhimurium that you believe is a toxin. Wheneveryou attempt to purify the protein from lysed cell cultures, you get two forms of the protein. One form is smaller than the other and is missing 15 amino acids from the N-terminus compared to the larger form. This leads you to hypothesize thatA) there are two termination sites in the mRNA.B) the protein requires chaperonins to fold properly.C) the protein is secreted and folds outside of the cell.D) you need to re-do the experiment because there should only be one form.

Back 43

the protein is secreted and folds outside of the cell.

Front 44

Transcription in eukaryotes occurs in theA) RNA polymerase.B) endoplasmic reticulum.C) cytoplasm.D) nucleus.

Back 44

D) nucleus.

Front 45

During DNA replication Okazaki fragments are linked together by________, an enzyme thatcreates phosphodiester bonds between nicked fragments of DNA.A) exopolymeraseB) DNA gyraseC) topoisomeraseD) DNA ligase

Back 45

DNA ligase

Front 46

A triplet of bases on an mRNA molecule is known as a(n)A) amino acid.B) anticodon.C) codon.D) ribosome-binding sequence.

Back 46

codon.

Front 47

Each adenine-thymine base pair has ________ hydrogen bonds, while each guanine-cytosinebase pair has ________ hydrogen bonds.A) two / oneB) two / threeC) four / threeD) three / two

Back 47

two / three

Front 48

In DNA replication there are leading and lagging strands, becauseA) DNA replication is conservative and a completely new DNA molecule must be made.B) DNA replication is semiconservative and each strand is copied simultaneously in opposite directions.C) the strands of DNA are parallel and are copied in the same direction simultaneously.D) one strand of DNA is copied faster than the other.

Back 48

DNA replication is semiconservative and each strand is copied simultaneously in oppositedirections.

Front 49

Most prokaryotic genomes are double-stranded circular DNA.

Back 49

TRUE

Front 50

2) Inverted repeats are common features of transcription termination sequences in all threedomains of life.

Back 50

TRUE

Front 51

In nature, the predominant form of DNA is supercoiled in a negative direction.

Back 51

TRUE

Front 52

Genes found on plasmids DO NOT impact metabolism or cellular structures.

Back 52

FALSE

Front 53

The genetic material in a virus is technically called a plasmid.

Back 53

FALSE

Front 54

DNA replication is bidirectional in prokaryotes with circular chromosomes.

Back 54

TRUE

Front 55

7) RNA acts at both the genetic and the functional levels.

Back 55

TRUE

Front 56

RNA is incapable of forming secondary structure.

Back 56

FALSE

Front 57

Aminoacyl-tRNA synthetase catalyzes the reaction between the appropriate amino acid andATP to form an activated amino acid: amino acid + ATP ↔ aminoacyl-AMP + P-P.

Back 57

TRUE

Front 58

The formation of new DNA does NOT require energy.

Back 58

FALSE

Front 59

rRNA has an enzymatic role in all stages of protein synthesis.

Back 59

TRUE

Front 60

Proteins known as chaperones are found only in Bacteria.

Back 60

FALSE

Front 61

Throughout the living world, the genetic code is generally universal; however, there areslight variations.

Back 61

TRUE

Front 62

DNA replication involves the synthesis of an RNA primer on one strand of the DNA.

Back 62

TRUE

Front 63

Regulation of an enzyme's activity occursA) transcriptionally.B) translationally.C) posttranslationally.D) at any point on the enzymatic production pathway.

Back 63

C) posttranslationally.

Front 64

When arginine is added to a culture growing exponentially in a medium without arginine,what occurs?A) All cellular growth ceases.B) Growth continues, but the production of enzymes required for the synthesis of arginine ceases.C) Growth continues, but the production of enzymes required for the synthesis of arginine increases.D) The cell returns to the lag stage of growth to synthesize the proteins necessary for the metabolism of arginine.

Back 64

Growth continues, but the production of enzymes required for the synthesis of arginineceases.

Front 65

Regulatory proteinsA) are influenced by small molecules.B) bind to specific DNA sites.C) regulate transcription.D) regulate transcription, bind specific DNA sites, and can be influenced by small molecules.

Back 65

regulate transcription, bind specific DNA sites, and can be influenced by small molecules.

Front 66

A protein region with a specific function and structure is called aA) conserved site.B) domain.C) locale.D) motif.

Back 66

B) domain.

Front 67

Transcriptional regulators bind most frequently at the ________ site of DNA.A) major grooveB) minor grooveC) histone complexD) primary supercoil

Back 67

A) major groove

Front 68

Which type of regulator(s) specifically bind to operator regions of DNA?A) activatorsB) activators and inducersC) repressorsD) repressors and corepressors

Back 68

C) repressors

Front 69

The lac operon is an example of ________ control in which the presence of an ________ isrequired for transcription to occur.A) negative / activatorB) negative / inducerC) positive / activatorD) positive / inducer

Back 69

B) negative / inducer

Front 70

Enzyme induction occursA) when the substrate is present.B) when the organism is environmentally stressed.C) continuously.D) when the substrate is depleted.

Back 70

when the substrate is present.

Front 71

Considering the catabolite repression mechanism, which observation would make you suspectit is NOT occurring?A) CRP bound to promoter sites B) elevated levels of transcripts for maltose and sucrose catabolism C) relatively low intracellular cyclic AMP levelsD) RNA polymerase bound to biosynthetic promoter sequences

Back 71

relatively low intracellular cyclic AMP levels

Front 72

During a growth curve of Aliivibrio fischeri, when would you expect to see the strongestbioluminescence?A) lag phaseB) early to middle log phaseC) late log to early stationary phaseD) middle to late stationary phase

Back 72

C) late log to early stationary phase

Front 73

What occurs when an inducer is added to an environment containing an organism with ametabolic pathway controlled by a repressor?A) The inducer combines with the repressor and activates the pathway.B) The inducer combines with the repressor and inactivates the pathway.C) The inducer combines with the substrate and blocks induction.D) The inducer does not combine with, but functions as a chaperone molecule for, the enzyme-substrate complex.

Back 73

The inducer combines with the repressor and inactivates the pathway.

Front 74

Which of the following do NOT bind to the promoter sequence during regulation?A) activatorsB) inducersC) repressorsD) activators, inducers, and repressors

Back 74

activators, inducers, and repressors

Front 75

Cyclic AMP is synthesized from ATP by an enzyme called ________ which is involved in________.

A) adenylate cyclase / catabolite repressionB) adenylate cyclase / transcriptional activationC) cAMP receptor protein (CRP) synthase / catabolite repressionD) cAMP receptor protein (CRP) synthase / transcriptional activation

Back 75

A) adenylate cyclase / catabolite repression

Front 76

In negative control of transcription, how does the presence of an inducer affect transcription?A) The inducer binds to the operator.B) The inducer does not bind to the operator.C) The inducer causes the repressor to bind to the operator.D) The inducer prevents the repressor from binding to the operator.

Back 76

D) The inducer prevents the repressor from binding to the operator.

Front 77

Which type of regulatory protein(s) is/are present in Archaea?A) Activators that stimulate RNA polymerase activity are present in Archaea.B) Repressors that block RNA polymerase activity are present in Archaea.C) Both activators and repressors are present in Archaea.D) Similar to regulation in Eukarya, Archaea lack bacterial-like regulators such as activators and repressors and use transcription factors instead.

Back 77

Repressors that block RNA polymerase activity are present in Archaea.

Front 78

The function of a kinase isA) methylation.B) response regulation.C) phosphorylation.D) glycosylation.

Back 78

phosphorylation.

Front 79

The promoters of positively controlled operons require activator proteins, becauseA) RNA polymerase easily recognizes the consensus sequence.B) they are required to inactivate the repressor proteins.C) the promoters have nucleotide sequences that bind RNA polymerase weakly, which are not close matches to the consensus sequence.D) they are needed to bind to the allosteric site of RNA polymerase.

Back 79

the promoters have nucleotide sequences that bind RNA polymerase weakly, which are notclose matches to the consensus sequence.

Front 80

To be most sensitive to a repellant, a methyl-accepting chemotaxis protein must be ________methylated to initiate a ________.A) fully / runB) fully / tumbleC) not / runD) not / tumble

Back 80

fully / tumble

Front 81

The most frequent way in which regulatory RNA molecules exert their effects is byA) base pairing with other RNA molecules that have regions of complementary sequence.B) binding to a repressor and repressing enzyme transcription.C) acting as an inducer that then binds to an activator protein to allow transcription to proceed.D) signal transduction.

Back 81

base pairing with other RNA molecules that have regions of complementary sequence.

Front 82

When a Bacillus anthracis population suddenly must form spores to survive a harsh nutrientpoor environment, how do the cells obtain energy?A) Cells in a growth phase that have not used up all of their energy will be the only ones to make endospores, which is why relatively few endospores are often made from a large population.B) Intracellular energy reserves are quickly made available to produce endospores.C) Slow responding cells are cannibalized by others that already began spore formation.D) Global regulation is initiated to minimize energy waste in biosynthetic pathways and catabolic pathways are increased to consume remaining usable substrates to fuel spore formation.

Back 82

Slow responding cells are cannibalized by others that already began spore formation.D) Global regulation is initiated to minimize energy waste in biosynthetic pathways and

Front 83

Interpret the results to the following experiment. Transcriptional activity of chemotacticgenes showed a high expression level during the following conditions: repelling away from compound 1, moving towards compound 2, and remaining sessile when presented compounds 3 and 4.A) Activity during movement in any direction led to high measurements observed, and the sessile population responded equally to both a chemoattractant and a chemorepellant but remained in the same location for their net movement.B) Gene expression by itself cannot distinguish between cells responding to both an attractant and repellent, so this ambiguity makes transcriptomics unfavorable but nonetheless indicates activity.C) The activity observed during a sessile existence suggests the molecular probe was targeting a chemotactic gene that is also involved in other non-chemotactic functions due to the activity observed.D) Transcriptomics as a whole cannot be used for chemotaxis genes because they are not regulated at the transcriptional level (i.e., they are constitutive), which is why activity is observed on all three conditions.

Back 83

Transcriptomics as a whole cannot be used for chemotaxis genes because they are notregulated at the transcriptional level (i.e., they are constitutive), which is why activity is observed on all three conditions.

Front 84

Based on their abundance and location in bacterial genomes, deduce which is LEAST likelyto horizontally transfer into another bacterium while maintaining its identical function and regulatory roles.A) heat shock protein-encoding geneB) lac operonC) catabolic regulonD) quorum sensing operon

Back 84

C) catabolic regulon

Front 85

In Bacteria, sensor kinases that respond to extracellular signals transfer this signal to thecytoplasmic machinery by typically phosphorylating the ________ residues.A) histidineB) serineC) threonineD) tyrosine

Back 85

A) histidine

Front 86

Which enzyme would be BEST to include in a protein extract to refold and denatureimproperly folded proteins?A) DnaKB) RepAC) RpoHD) Spo0A

Back 86

C) RpoH

Front 87

Bacteria from the genus Caulobacter are used to model cellular differentiation in eukaryotes.The abundance of CtrA, DnaA, and GcrA separately control activity of other genes necessary for differentiation in Caulobacter. Thus, these three proteins can be classified asA) activating sensors.B) heterologous regulators.C) differentiating regulons.D) transcriptional regulators.

Back 87

transcriptional regulators.

Front 88

Which statement is TRUE of two separate regulators controlling one individual operon?A) The two regulators themselves must respond to different signals, which enables both to control the operon differently.B) One regulator will likely control the transcription of one section of the operon, whereas the other regulator will control the other component.C) One regulator will bind to the operator region whereas the other will bind to the promoter region so they can co-occur and co-regulate the operon.D) Two regulators trying to control the same operon will likely result in only one being maintained after several generations.

Back 88

The two regulators themselves must respond to different signals, which enables both tocontrol the operon differently.

Front 89

How would you design an sRNA to bind to a sequence?A) select six continuous nucleotides from the sequenceB) take the complementary sequence of six continuous nucleotidesC) select 200 continuous nucleotides from the sequenceD) take the complementary sequence of 200 continuous nucleotides

Back 89

D) take the complementary sequence of 200 continuous nucleotides

Front 90

Which of the following mechanisms leads to INCREASED transcriptional activity?A) An sRNA binds to the ribosome binding site.B) Ribonuclease activity is blocked by sRNA complementary binding to the end of a transcript.C) The ribosome binding site is made available from sRNA binding to part of it.D) Recruitment of RNA polymerase is enhanced when sRNA binds to and removes a repressor.

Back 90

The ribosome binding site is made available from sRNA binding to part of it.

Front 91

When the nontemplate strand of a gene is transcribed into RNA, what is likely to result?A) A complementary sRNA will bind to it and form a functional ribozyme with secondary structure.B) It will complementary bind to the gene sequence, form a hairpin loop, and transcriptionally repress the gene.C) The complementary mRNA also transcribed from the template strand will bind to it and halt its translation.D) A global regulator will identify this as a stress, respond by inducing ribonuclease production, and it will degraded.

Back 91

The complementary mRNA also transcribed from the template strand will bind to it and haltits translation.

Front 92

How could you identify potential riboswitches with bioinformatics tools?A) Advanced 3D modeling techniques of mRNA folding would be necessary because complementary nucleotide binding predictions would not be useful.B) Locate short regions of an individual transcript with several complementary sites.C) Identify homologous sRNAs in other organisms.D) Identify several complementary mRNAs encoded in the genome.

Back 92

Advanced 3D modeling techniques of mRNA folding would be necessary becausecomplementary nucleotide binding predictions would not be useful.

Front 93

Based on our understanding of the early stages of life, ________ is/are thought to be one ofthe earliest forms of metabolic regulation that evolved.A) attenuationB) feedback inhibitionC) riboswitchesD) transcription factors

Back 93

riboswitches

Front 94

Attenuation is a type of regulation that can controlA) allosteric enzyme activity.B) transcriptional activity exclusively.C) translational activity exclusively.D) both transcriptional and translational activity.

Back 94

transcriptional activity exclusively.

Front 95

Post-translational regulation of an enzyme's activity, such as glutamine synthetase, can befinely controlled at varied levels due toA) the varied strengths metabolite-regulating compounds can have with the enzyme such as hydrogen bonding, covalent bonding, and van der Waals attractions.B) having multiple independently functional subunits.C) the structural strength enzymes have once properly folded compared to short-lived and easily degradable transcripts during translational regulation.D) weak chemical modifications of the enzyme rather than harsh protein-protein or protein-DNA interactions.

Back 95

having multiple independently functional subunits.

Front 96

Which of the following IS a characteristic of an isoenzyme?A) More than one enzyme is regulated by the same mechanism.B) The same reaction can be catalyzed by multiple enzyme variants.C) Multiple binding sites on the same enzyme enable multiple regulation mechanisms.D) More than one gene makes the same enzyme.

Back 96

The same reaction can be catalyzed by multiple enzyme variants.

Front 97

Which regulatory mechanism does NOT depend on a conformational change inprotein/enzyme structure to change activity?A) attenuationB) catabolite repressionC) feedback inhibitionD) negative control

Back 97

attenuation

Front 98

An organism grown in a high nutrient liquid broth to high turbidity always appears toproduce a blue pigment and even when a large inoculum is transferred to a nutrient rich agar plate it appears blue. When the researcher noticed it never appears blue when very small colonies were grown in low nutrient agar plates. What is the most plausible conclusion?A) Large populations enabled the differentiation of a subpopulation of cells that created the blue pigment.B) Only high nutrient conditions provide enough energy for cells to produce this secondary metabolite that appears blue.C) The blue pigment production is linked to quorum sensing.D) The strong gradient from very high to low nutrient bioavailability induces production of the blue metabolite.

Back 98

The blue pigment production is linked to quorum sensing.

Front 99

A bacterium that either partially or fully catabolizes an acyl-homoserine lactone will likelydisruptA) attenuation.B) chemotaxis.C) endospore formation.D) quorum sensing.

Back 99

quorum sensing.

Front 100

Phosphorylation of ________ regulates which direction a flagellum rotates, thus controllingwhether an organism runs or tumbles.A) CheAWB) CheBC) CheYD) CheZ

Back 100

C) CheY

Front 101

What are the primary regulator units that control endospore formation?A) allosteric proteinsB) antisense RNAsC) riboswitchesD) sigma factors

Back 101

sigma factors

Front 102

During the biotransformation of a large molecular weight compound, two major products areformed. While one of the products is catabolized, the other compounds accumulation represses the biotransformation of the large compound. Which approach is MOST likely to artificially enhance the biotransformation beyond this point in a batch culture?A) addition of an isoenzyme for the biotransformation route to increase its transcriptionB) addition of inducer molecules into the medium to increase transcriptional repressionC) inclusion of more of an intermediate compound in the catabolic pathwayD) spike in additional activator proteins that control the transcription of this pathway

Back 102

addition of an isoenzyme for the biotransformation route to increase its transcription

Front 103

Quorum sensing generally follows the mechanism of which type of regulation?A) feedback inhibitionB) negative transcriptional regulationC) positive transcriptional regulationD) two-component regulation system

Back 103

two-component regulation system

Front 104

What type of sRNA often requires a chaperon protein for strong regulation activity?A) antisense RNAB) riboswitchesC) siRNA D) trans-sRNA

Back 104

trans-sRNA

Front 105

Which organism would likely harbor the MOST two-component regulatory systems?A) an archaeon living in an extreme environmentB) a bacterium occupying a heterogeneous niche will high nutrient mixingC) an organism capable of quorum sensingD) a parasitic bacterium living inside another organism

Back 105

a bacterium occupying a heterogeneous niche will high nutrient mixing

Front 106

How is the activity of a riboswitch controlled?A) by other riboswitchesB) metabolite binding can change its structureC) sigma factor binding alters its structureD) small RNA complementary binding disrupts its function

Back 106

metabolite binding can change its structure

Front 107

45) Transcriptomics is a common approach to infer which metabolic pathways are actively functioning, but which regulation process can MOST significantly complicate or even abolish conclusions from this approach?A) activity of a catabolite repressor protein on multiple pathwaysB) antisense RNA silencingC) feedback inhibition with allosteric proteinsD) presence of corepressors and inducers which are molecules undetected by transcriptomics

Back 107

antisense RNA silencing

Front 108

Proteins required at approximately the same level throughout a cell's growth cycle are oftennot subject to regulatory mechanisms and are constitutively synthesized.

Back 108

TRUE

Front 109

Short regions at the beginning and end of gene sequences are not translated into proteins.

Back 109

TRUE

Front 110

3) Small molecules usually act directly (rather than indirectly) in regulating transcription.

Back 110

FALSE

Front 111

4) A common structure for proteins that bind DNA is helix-turn-helix.

Back 111

TRUE

Front 112

The actual residues in a DNA-binding protein that interacts with DNA usually correspond toeach other according to the amino acids encoded by the DNA. For example, a DNA sequencing containing AGC-AGA-CAG which encodes for Ser-Arg-Gln would likely have a DNA-binding protein with Ser-Arg-Gln bind to it.

Back 112

FALSE

Front 113

Some proteins that bind to DNA block transcription, whereas other proteins can activatetranscription.

Back 113

TRUE

Front 114

The biodegradation pathway for benzoate is likely to be subject to induction rather thanrepression.

Back 114

Answer: TRUE

Front 115

A repressor is a molecule that represses biosynthesis of an mRNA transcript.

Back 115

Answer: FALSE

Front 116

Once the regulatory proteins and effector molecules are made, the actual mechanisms forregulation rarely require net energy input.

Back 116

Answer: TRUE

Front 117

Depending on the type of regulatory mechanism, activators and repressors can bind tooperator regions which control transcription.

Back 117

FALSE

Front 118

11) A regulon always includes at least two operons.

Back 118

TRUE

Front 119

Transcriptional regulation is considered negative when an inducer binds to and deactivates arepressor.

Back 119

Answer: TRUE

Front 120

The preferential use of glucose over other available carbon substrates for growth ismechanistically explained by catabolite repression.

Back 120

TRUE

Front 121

Proteins and RNA molecules that are needed in the cell, at about the same level under allgrowth conditions, require constitutive expression.

Back 121

TRUE

Front 122

Studying the transcriptional activity of flagellar genes would not likely reveal differentialchanges when the cells are actively motile compared to nonmotile activity, because a two-component regulatory system is sufficient to control flagellar activity.

Back 122

Answer: TRUE

Front 123

A two-component regulatory system usually involves both the sensor and response proteinsbeing subject to phosphorylation.

Back 123

Answer: TRUE

Front 124

DNA-binding proteins typically affect translation of a protein.

Back 124

Answer: FALSE

Front 125

Cyclic AMP (cAMP) is involved in the global regulation of catabolic pathways inEscherichia coli, including the lac operon, and a low activity of adenylate cyclase that makes cAMP is suggestive of catabolite repression.

Back 125

Answer: FALSE

Front 126

Once cytoplasmic sensor proteins involved in chemotaxis regulation are phosphorylated, acascade of other phosphate-transferring mechanisms provide ATP energy to rotate flagella.

Back 126

Answer: FALSE

Front 127

In most cases, the first product of a particular biosynthetic pathway represses the enzymes ofthe pathway.

Back 127

FALSE

Front 128

In catabolic repression, cells use the least abundant carbon source first.

Back 128

FALSE

Front 129

Quorum sensing requires a strong gradient to be reached before the signaling molecules aretransported into the cytoplasm.

Back 129

FALSE

Front 130

During chemotaxis, attractants increase the rate of autophosphorylation whereas repellantsdecrease this rate.

Back 130

FALSE

Front 131

Multiple sigma factors are essential to induce the biosynthesis of endospores, all of which areencoded by genes, so a complex regulatory mechanism such as this likely has a higher chance of mutations leading to incorrect functioning compared to a simple repression mechanism.

Back 131

TRUE

Front 132

Heat shock proteins are produced at high numbers to minimize damaging effects during highheat conditions as well as other stress signals unrelated to heat such as ultraviolet radiation.

Back 132

TRUE

Front 133

Multiple mechanisms for small RNA (sRNA)-mediated translational regulation exist but allare unified by inactivating protein synthesis of the target mRNA.

Back 133

FALSE