UKY BIO308 (exam 2)
A mutation in the operator region of an operon would most likely cause the operon A. to be unable to bind the repressor protein B. to prevent sigma factor binding C. To produce a nonfunctional protein D. to be constitutively inactive E. to code for an incorrect amino acid at the start codon
A. to be unable to bind the repressor protein
Enzyme activity can be most rapidly changed at which level? Choose one: A. Transcription of the DNA encoding the enzyme B. Posttranslational modification of the enzyme C. Translation of the enzyme from the mRNA encoding it D. Control of mRNA stability
B. Posttranslational modification of the enzyme
All of the following are potential mechanisms of horizontal gene transfer except Choose one: A. specialized transduction. B. generalized transduction. C. transformation. D. binary fission. E. conjugation.
D. binary fission.
Transcriptional regulation is normally accomplished by the reversible binding of regulatory proteins. The proteins that activate genes typically bind to sequences (UPSTREAM OR DOWNSTREAM OF) the promoter, whereas those involved in repression usually bind (UPSTREAM OR DOWNSTREAM OF ) the promoter.
1) Upstream 2) Down stream
In 1928, a physician named Frederick Griffith was investigating the virulence of Streptococcus pneumoniae. He first determined that mice exposed to an encapsulated strain of S. pneumoniae (which formed smooth colonies) died. Mice infected with a nonencapsulated strain (which formed rough colonies) lived. In a now-famous experiment, he coinjected mice with heat-killed cells of virulent S. pneumoniae and cells from a live nonencapsulated strain. Amazingly, the mice died and a live virulent strain was recovered that formed smooth colonies. It was later discovered that Choose one: A. the live cells were transformed with DNA from the dead virulent cells. B. the dead virulent cells were resurrected once inside the living host. C. the mice had subclinical infections of S. pneumoniae and became sick during the experiment. D. the live harmless cells mutated into a virulent strain once in the mice. E. the injected cell preparations were contaminated with live virulent S. pneumoniae.
A. the live cells were transformed with DNA from the dead virulent cells.
The process indicated by the arrow in the figure above represents A) lagging strand synthesis. B) leading strand synthesis. C) transcription. D) translation. E) homologous recombination.
A) lagging strand synthesis.
The uptake of DNA released from a cell is ________, while transfer of DNA with cell-to-cell contact would most likely result in ________. A) transformation / conjugation B) transduction / conjugation C) conjugation / transformation D) transformation / transduction
A) transformation / conjugation
If a segment of RNA reads 5′ GCCUUAA 3′, then the corresponding DNA template strand reads Choose one: A. 5′ TTAAGGC 3′. B. 5′ CGGAATT 3′. C. 5′ GCCUUAA 3′. D. 5′ GCCTTAA 3′.
A. 5′ TTAAGGC 3′.
What are the components common to all virions? A. DNA or RNA genome B. DNA and RNA genomes C. envelope D. capsid
A. DNA or RNA genome and D. capsid
You have isolated a newly discovered viral strain and sequenced its genome. The genome contains 30% adenine, 40% guanine, 25% cytosine, and 5% thymine. You conclude that the virus has a single-stranded DNA genome. Based on what evidence can you make this conclusion? Choose one: A. Double-stranded genomes have equal amounts of adenine and thymine. B. Single-stranded genomes have a higher rate of mutations. C. Single-stranded genomes always have a high percentage of purines. D. Double-stranded genomes have equal amounts of adenine and guanine.
A. Double-stranded genomes have equal amounts of adenine and thymine.
The enzyme DNA primase is a(n) Choose one: A. RNA polymerase. B. exonuclease. C. ligase. D. DNA polymerase.
A. RNA polymerase.
Which of the following features would increase the chances of foreign DNA being stably maintained by a recipient cell? Choose one or more: A. The DNA is circular and capable of self-replication. B. A portion of the DNA shares 100% identity with a spacer in the cell's CRISPR region. C. The foreign DNA has insertion sequences (elements). D. It shares extensive homology with one or more host genes. E. Its methylation pattern differs from the host DNA.
A. The DNA is circular and capable of self-replication. C. The foreign DNA has insertion sequences (elements). D. It shares extensive homology with one or more host genes.
The protein product of the lacI gene is Choose one: A. a regulatory protein. B. an activator. C. sensor kinase. D. a corepressor.
A. a regulatory protein.
When considering operons, the role of the repressor is to ____. A. bind the operator and block transcription B. bind the promoter and block transcription C. bind to the co-repressor proteins and activate them D. bind to the activator protein and inactivate it E. bind RNA polymerase and inactivate it
A. bind the operator and block transcription
In E. coli, eight enzymatic steps are involved in the biosynthesis of arginine from glutamate. The synthesis of the required enzymes is subject to control by the ArgD protein, which, on its own, binds weakly to a regulatory sequence just downstream of the promoter regions for these genes. Upon the addition of excess arginine to the growth medium, the respective mRNA molecules are no longer produced. What is the likely role of arginine in the control of these genes? Choose one: A. corepressor B. operator C. repressor D. activator E. inducer
A. corepressor
Bacterial genomes Choose one: A. depend on the species. B. are several circular chromosomes. C. are several linear chromosomes. D. are a single circular chromosome
A. depend on the species.
The gene that codes for a protein involved in detoxifying an environmental toxin is only expressed in the presence of the toxin. A repressor protein controls transcription of the gene. The toxin mediates _________ of the gene by __________. A. induction; relieving repression imposed by the repressor B. induction; stimulating activation mediated by an activator C. repression; relieving repression imposed by the repressor D. repression; stimulating activation mediated by an activator
A. induction; relieving repression imposed by the repressor
A _____ virus cycle leads only to cell lysis, and a _____ virus cycle involves phage genome integration into the host genome. Choose one: A. lytic; lysogenic B. lysogenic; virulent C. lysogenic; lytic D. temperate; lysogenic
A. lytic; lysogenic
DNA replication is started with a(n) ____, which, in most cases, in vivo is a short stretch of _____ A. primer/RNA B. Primer/DNA C. promoter/DNA D. promoter/ RNA E. consensus sequence/RNA
A. primer/RNA
Denaturation of DNA refers to Choose one: A. the separation of the double helix into single strands. B. the breaking of covalent bonds between the nitrogenous bases and the sugars. C. when the phosphodiester bonds between adjacent sugars break. D. the double-stranded DNA supercoils.
A. the separation of the double helix into single strands.
One advantage to using sRNAs to control protein expression is that Choose one: A. translation of the sRNA is not needed, thus saving amino acids. B. sRNA is not specific, so many proteins can be downregulated at once. C. transcription of the sRNA is not needed, thus saving nucleotides. D. they cannot damage the DNA, being made of nucleotides as well.
A. translation of the sRNA is not needed, thus saving amino acids.
A wild-type organism and a genetic variant both have a gene encoding a receptor producing a chemotactic response to metabolite A. The genetic variant has a mutation in a regulatory gene for expression of the receptor. Which of the following statements with respect to the receptor is CORRECT? A) The genotypes and phenotypes of both organisms are the same. B) The organisms have the same receptor genotype but different phenotypes. C) The organisms have different genetic sequences for the receptor. D) The phenotypes of both organisms are the same, but the genotypes differ E) The answer cannot be determined from the information provided.
B) The organisms have the same receptor genotype but different phenotypes.
How do all viruses differ from bacteria? A) Viruses are obligate intracellular parasites. B) Viruses are not composed of cells. C) Viruses do not have any nucleic acid. D) Viruses are filterable. E) Viruses do not reproduce.
B) Viruses are not composed of cells.
AT-rich DNA will denature/melt A) 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.
B) at a lower temperature than GC-rich DNA.
Which of the following is characteristic of prokaryotic genomes but NOT eukaryotic genomes? A) histones B) circular chromosomes C) linear chromosomes D) enclosed in a nuclear membrane E) typically consist of a few to several chromosomes
B) circular chromosomes
Which type of regulator(s) specifically bind to operator regions of DNA? A) activators B) repressors C) activators and corepressors D) activators and inducers
B) repressors
Most sigma factors are highly conserved and help RNA polymerases identify the beginning of genes. They accomplish this by binding to which of the following sites on promoters? Choose one: A. -1 and +35 sites B. -10 and -35 sites C. +1 and +35 sites D. +10 and +35 sites E. +1 and +10 sites F. -1 and +10 sites
B. -10 and -35 sites
You are trying to demonstrate the mechanism of horizontal gene transfer between something in flask A and bacteria in Flask B. If the mechanism is conjugation, which of the following treatments would stop the transfer? A. DNAse digestion B. Blocking cell-cell contact C. filtering out viral particles
B. Blocking cell-cell contact
Which of the following types of enzymes would a virus need to provide in order to replicate within a cell? A. DNA-dependent DNA polymerases for DNA viruses B. RNA replicases (RNA-dependent RNA polymerases) for RNA viruses C. DNA-dependent RNA polymerases for RNA viruses D. DNA-dependent RNA polymerases for DNA viruses
B. RNA replicases (RNA-dependent RNA polymerases) for RNA viruses
CRISPR is Choose one: A. an enzyme that cleaves DNA that is unmethylated. B. a set of short DNA sequences that allow the bacterium to "remember" past infections. C. used to make DNA from RNA. D. a protein component of the capsid.
B. a set of short DNA sequences that allow the bacterium to "remember" past infections.
Sigma factors are responsible for Choose one: A. helping replicate the DNA helix. B. binding of RNA polymerase to consensus sequences on DNA. C. mRNA binding to promoter regions. D. nonselective binding of RNA polymerase to DNA.
B. binding of RNA polymerase to consensus sequences on DNA.
Riboswitches are RNA molecules that can Choose one: A. repress operator regions of the DNA. B. inhibit translation by preventing access to the ribosomal binding site. C. inhibit post-translation protein modifications. D. act as enzymes.
B. inhibit translation by preventing access to the ribosomal binding site.
Which of the following represents the fastest and most easily reversible way for a cell to alter its physiology? Choose one: A. activating transcription by relieving repression B. modification of an existing protein C. use of a transcriptional activator to upregulate a gene D. regulating translation of an existing mRNA E. DNA sequence rearrangements
B. modification of an existing protein
In addition to acquiring genes via conjugation, transduction, and transformation, natural selection may also favor loss of genes from an organism's genome. In which of the following bacteria would you most likely expect to find evidence of beneficial genome reduction? Choose one: A. opportunistic pathogen B. obligate intracellular pathogen C. harmless gut commensal D. free-living soil bacterium E. aquatic stalked bacterium
B. obligate intracellular pathogen
At which point would regulation be most efficient in conserving energy and materials if the gene products are not needed in a cell: A. regulation of translation B. regulation of transcription C. post-transcriptional regulation D. post-translational regulation
B. regulation of transcription
Accumulation of the heat-shock sigma factor, sigma H, increases at high temperatures because at high temperatures, Choose one: A. proteolysis of sigma H increases. B. sigma H mRNA adopts an unfolded secondary structure. C. fewer chaperone proteins are expressed. D. H has a reduced affinity for RNA polymeras
B. sigma H mRNA adopts an unfolded secondary structure.
DNA is __________ into mRNA and mRNA is _________ into proteins. Choose one: A. replicated; hydrolyzed B. transcribed; translated C. translated; replicated D. translated; transcribed
B. transcribed; translated
The most frequent way in which regulatory RNA molecules exert their effects is by A) acting as an inducer that then binds to an activator protein to allow transcription to proceed. B) signal transduction. C) base pairing with other RNA molecules that have regions of complementary sequence. D) binding to a repressor and repressing enzyme transcription.
C) base pairing with other RNA molecules that have regions of complementary sequence.
According to the operon model, for the synthesis of an inducible enzyme to occur, the A) end-product must not be in excess. B) substrate must bind to the enzyme .C) substrate must bind to the repressor. D) repressor must bind to the operator E) repressor must not be synthesized.
C) substrate must bind to the repressor.
Compared with cellular genomes, viral genomes Choose one: A. are larger, with more base pairs. B. are approximately the same size as the genome of the organisms they infect. C. also must have double-stranded DNA as their genome. D. are smaller, with fewer base pairs.
D. are smaller, with fewer base pairs.
DNA REPLICATION STEPS---Order the following steps chronologically: A. Binding proteins stablilze the double helix B. DNA Pol III adds complementary nucleotides C. DNA gyrase removes DNA supercoils D. DnaA initiates replication E. DNA Pol I replaces the RNA primer F. DNA helicase unwinds the DNA double helix G. Primase Generates an RNA primer that binds to the origin H. DNA ligase seals any nicks in the DNA
C, F, A, D, G, B, E, H
Analysis of the genome of a newly discovered bacterial strain reveals that it is composed of a double-stranded DNA molecule containing 16% thymine. Based on this information, what would you predict the percentage of cytosine to be? Choose one: A. 68% B. 32% C. 34% D. 16%
C. 34%
What is the role of the first structural gene (lacZ) in the lac operon? Select all that apply. Choose one or more: A. It transports lactose into the cell. B. It binds to and inactivates the lac repressor. C. It breaks down lactose into glucose and galactose. D. It isomerizes lactose into allolactose. E. It causes cAMP levels to rise in the presence of increasing concentrations of lactose.
C. It breaks down lactose into glucose and galactose. D. It isomerizes lactose into allolactose.
For gram (-) bacterium such as E. Coli, the four major destinations for extracytoplasmic proteins (non-cytoplasmic) are the plasma membrance, extracellular space, outer membrane and __________. A. Fimbriae B. Capsule C. Periplasm D. Pili
C. Periplasm
If an inducible operon is actively transcriped (turned on), A. the corepressor is present B. the corepressor is absent C. the inducer is present D. the inducer is absent E. either the corepressor is absent or the inducer is present
C. The inducer is present
Why is it incorrect to refer to conjugation as bacterial sex? Choose one or more: A. It does not require physical contact. B. The transferred DNA cannot replicate. C. The transferred DNA is not required for normal cellular function. D. It does not involve gametes. E. The recipient is haploid for the transferred genes.
C. The transferred DNA is not required for normal cellular function. D. It does not involve gametes. E. The recipient is haploid for the transferred genes.
What two conditions must be met to produce a heritable mutation? Choose one or more: A. The change must occur within a particular gene. B. The change must result in a change in cellular phenotype. C. There is a change in the DNA sequence. D. The mutation does not get repaired before the cell divides. E. Some form of horizontal gene transfer is involved.
C. There is a change in the DNA sequence. D. The mutation does not get repaired before the cell divides.
Which of the following is NOT true concerning all plasmids? Choose one: A. They may exist in multiple copies in a single cell. B. They may be transmitted horizontally from one bacterium to another. C. They are always linear DNA. D. They may contain antibiotic resistance genes.
C. They are always linear DNA.
A structural gene is Choose one: A. a string of nucleotides that can be decoded by an enzyme to produce a protein. B. an enzyme involved in the conversion of DNA into RNA. C. a string of nucleotides that can be used as a template to produce an RNA that codes for a protein. D. an organism's entire genetic complement of DNA.
C. a string of nucleotides that can be used as a template to produce an RNA that codes for a protein.
Anti-anti-sigma factors Choose one: A. bind and block sigma factors twice as well as anti-sigma factors. B. are housekeeping genes and are constitutively expressed. C. bind anti-sigma factors, releasing sigma factors to activate transcription. D. are only found in eukaryotic microbes.
C. bind anti-sigma factors, releasing sigma factors to activate transcription
Various sigma factors play a role in gene expression by Choose one: A. bringing about an early termination due to hairpins in the message. B. using alternate nucleotides to promote different genes. C. binding to a variety of different -10 and -35 sequences. D. allowing for binding of various enhancer proteins to aid initiation.
C. binding to a variety of different -10 and -35 sequences.
A "mosaic" genome refers to one that Choose one: A. is decorated with DNA-binding proteins. B. undergoes crossover during meiosis. C. contains large segments of DNA from different sources and events. D. has sites where double-stranded breaks are constantly being made and rejoined. E. contains segments of dsRNA interspersed with DNA.
C. contains large segments of DNA from different sources and events.
Viral genomes may comprise Choose one: A. single-stranded DNA. B. double-stranded RNA. C. double or single-stranded DNA or double or single-stranded RNA. D. double-stranded DNA.
C. double- or single-stranded DNA OR double- or single-stranded RNA
Eukaryotic genomes comprise mostly __________, whereas prokaryotes have mostly __________. Choose one: A. double-stranded DNA; single-stranded DNA B. positively supercoiled DNA; negatively supercoiled DNA C. noncoding DNA; coding DNA D. circular DNA; linear DNA
C. noncoding DNA; coding DNA
A(n) __________ is composed of DNA. Choose one: A. sensor kinase B. inducer C. operator D. response regulator
C. operator
A prophage is a Choose one: A. circular phage genome that promotes cell lysis. B. virus that promotes tumor growth in plants. C. phage genome integrated into a host genome. D. bacterial virus particle that has not yet infected a cell.
C. phage genome integrated into a host genome
Compared with the number of antibiotics, the number of antiviral drugs is small because Choose one: A. viruses are very similar in structure to human cells. B. there are not many viruses that infect humans. C. viruses use host cell machinery to replicate. D. viruses lack a genome and genomes are often the target for drugs.
C. viruses use host cell machinery to replicate
In a culture of bacteria, there are some individuals that are unable to synthesize histidine. What is the best and most likely description of how these individuals differ from the other bacteria in the culture? A) They differ in their phenotype but not in their genotype. B) They don't differ in genotype or phenotype. C) They differ in their genotype but not in their phenotype D) They differ in their genotype and in their phenotype.
D) They differ in their genotype and in their phenotype.
The bacterial chromosome is A) usually circular. B) found in a nucleoid. C) found in a nucleus. D) both circular and found in a nucleoid. E) both circular and found in a nucleus.
D) both circular and found in a nucleoid.
Which type of mutation would you predict might have the greatest effect on gene function? A) Silent mutation B) insertion of a transposon in an intron C) frameshift mutation in the fifth codon from the end of the gene sequence D) frameshift mutation near AUG codon E) nonsense mutation in the second-to-last codon
D) frameshift mutation near AUG codon
A plasmid may A) replicate independently of the chromosome. B) be transferred cell-to-cell during conjugation. C) be integrated into the chromosome D) replicate independently of the chromosome, integrate into the chromosome, or be transferred cell-to-cell during conjugation.
D) replicate independently of the chromosome, integrate into the chromosome, or be transferred cell-to-cell during conjugation.
Which enzyme is needed third? A. Primase B. DNA gyrase C. DnaA D. DNA helicase E. single stranded binding proteins
D. DNA helicase
Genes for which of the following functions would be constitutively expressed in a bacterial cell such as E. coli? Choose one: A. virulence B. heat shock C. osmotic stress D. DNA replication E. nitrogen limitation
D. DNA replication
in DNA replication, there are leading and lagging strands. This is because ____. A. DNA replication is conservative and a completely new DNA molecule must be made. B. one strand of DNA is copied faster than the other. C. The strands of DNA are parallel and are copied in the same direction simultaneously. D. DNA replication is semi-conservative and each strand is copied simultaneously in opposite directions E. Non of the above.
D. DNA replication is semi-conservative and each strand is copied simultaneously in opposite directions
Which sequence shows increasing numbers of genes? Choose one: A. Gene, regulon, operon B. Operon, gene, regulon C. Operon, regulon, gene D. Gene, operon, regulon
D. Gene, operon, regulon
A specific virus always infects Choose one: A. only a single species. B. a small number of closely related species in the same genus. C. a wide range of species. D. The number of species depends on the virus.
D. The number of species depends on the virus
An inducer causes gene expression by binding Choose one: A. directly to a consensus sequence on DNA. B. an activator protein to remove it from the DNA. C. a corepressor protein. D. a repressor protein to remove it from the DNA.
D. a repressor protein to remove it from the DNA.
Viruses infect Choose one: A. only archaea. B. only eukaryotes. C. only bacteria. D. all three domains of life.
D. all domains of life
The primary reason there is a repressible lac operon to metabolize lactose, but glucose metabolism genes are not controlled in a similar manner, is that Choose one: A. lactose costs too much energy to cross the membrane to have the genes on all the time. B. lactose is very rarely found in the environment. C. the regulatory system simply never evolved. D. glucose metabolism is critical to the cell's survival so the resulting proteins are always needed.
D. glucose metabolism is critical to the cell's survival so the resulting proteins are always needed.
The complementary nucleobase pairs in DNA are held together by which type of bonds? Choose one: A. peptide B. polar covalent C. phosphodiester D. hydrogen
D. hydrogen
The CRISPR system Choose one: A. unwittingly replicates bacteriophage DNA. B. promotes horizontal gene transfer following exposure to antibiotics. C. facilitates recombination through a complex system of proteins and clustered repeats. D. is a type of immunity that directs degradation of foreign DNA upon repeat exposure. E. randomly causes double-stranded breaks in any incoming DNA.
D. is a type of immunity that directs degradation of foreign DNA upon repeat exposure.
Compared with cells that are surrounded by a lipid membrane, viruses Choose one: A. are never surrounded by a lipid membrane. B. may be surrounded by a membrane synthesized by viral proteins. C. are also always surrounded by a lipid membrane. D. may be surrounded by a membrane derived from the host cell.
D. may be surrounded by a membrane derived from the host cell
The statement "codons are redundant" refers to the fact that Choose one: A. the same codon always appears twice in a row in an mRNA. B. most codons are used more than once in a given mRNA molecule. C. most codons can specify more than one amino acid. D. most amino acids are specified by more than one codon.
D. most amino acids are specified by more than one codon
Which of the following is likely found on the bacterial chromosome, not on a plasmid? A. Antibiotic resistance gene B. Fertility factors C. Gene for a toxin D. rRNA gene
D. rRNA gene
Most known sRNAs are responsible for Choose one: A. being charged with amino acids and aiding protein synthesis. B. forming part of the ribosome. C. forming complexes with the DNA to repress operons. D. regulating protein levels at the level of translation.
D. regulating protein levels at the level of translation.
During transcription elongation, what is the function of DNA topoisomerases? Choose one: A. removing negative supercoiling so that the promoter region is available for sigma factor B. opening the DNA to form the transcription bubble for RNA polymerase to begin C. identifying the region where termination will be taking place so that RNA polymerase can slow elongation before stopping D. removing positive DNA supercoils that are being produced by RNA polymerase E. coiling the DNA after RNA polymerase has passed by so that it is ready for the next round of transcription
D. removing positive DNA supercoils that are being produced by RNA polymerase
Which of the following modifications would likely cause constitutive expression of a gene that is normally regulated by an activator protein? Choose one: A. deleting the operator sequence downstream of the promoter B. deleting the transcription terminator C. modifying the activator protein so that it cannot bind the cognate inducer D. replacing the promoter with the consensus sequence for RpoD σ70 E. deleting the regulatory region of DNA that binds the activator-inducer
D. replacing the promoter with the consensus sequence for RpoD σ70
In a two-component signal transduction system, the __________ senses a change in the environment and the __________ changes gene expression. Choose one: A. sensor; inducer B. sensor; inhibitor C. regulator, initiator D. sensor, response regulator
D. sensor, response regulator
The difference between generalized and specialized transduction is A. the size of the plasmids being moved. B. the size of the phage being used. C. that in generalized transduction, chromosomes are moved, whereas in specialized transduction, plasmids are moved. D. that in generalized transduction, any DNA can be moved, but with specialized transduction, only certain DNA near the phage site can be moved. E. There is no difference.
D. that in generalized transduction, any DNA can be moved, but with specialized transduction, only certain DNA near the phage site can be moved.
Which of the following methods of horizontal gene transger involves DNA transfer from a dead/lkysed cell? A. transduction B. transformation C. conjugation D. A and B E. None of the above
D. transduction and transformation
Identify an infectious agent that is comprised of only a nucleic acid particle. Choose one: A. Virion B. prion C. bacteriophage D. viroid
D. viroid
Under what condition would a temperate bacteriophage infecting Staphylococcus aureus (an aerobic bacteria commonly found on the human body) be shifted by environmental cues from lysogeny to a lytic cycle? Choose one: A. when phage-infected cells are incubated at atmospheric levels of oxygen B. when phage-infected cells are placed on nutrient-rich media C. when phage-infected cells are incubated at 37°C D. when phage-infected cells are incubated at 50°C
D. when phage-infected cells are incubated at 50°C
Which of the following places these items in the correct order for DNA-virus replication? 1. Maturation 2. DNA synthesis 3. Transcription 4. Translation A) 4; 3; 2; 1 B) 4; 1; 2; 3 C) 3; 4; 1; 2 D) 1; 2; 3; 4 E) 2; 3; 4; 1
E) 2; 3; 4; 1
Which of the following is involved in translation? A) rRNA only B) tRNA only C) mRNA only D) both mRNA and tRNA E) mRNA, rRNA, and tRNA are all involved.
E) mRNA, rRNA, and tRNA are all involved.
All of the following enzymes are involved in DNA replication. Of those listed, which is third in the order: A. DNA helicase B. DNA ligase C. Primase D. DNA Pol I E. DNA Pol III
E. DNA Pol III (A --> C --> E --> D --> B)
A riboswitch can enhance transcription of a gene by Choose one: A. blocking access of repressor proteins to operator sites. B. promoting activation by cAMP-CRP. C. enhancing the affinity of RNA polymerase for the promoter. D. exposing the ribosomal binding site in the mRNA. E. preventing the formation of a transcription terminator stem.
E. preventing the formation of a transcription terminator stem.
_______ proteins prevent transcription, whereas __________ proteins stimulate transcription. A. Activators; repressors B. Inducers; corepressors C. corepressors; inducers D. regulators; repressors E. repressors; activators
E. repressors; activators
Most bacteria contain _______ that protect the cell from foreign DNA.
Restriction Enyzmes
Synonymous codons (those that code for the same amino acid) typically only differ in the base at position ______
Three (Third Position) (aka Wobble Base)
Increased synthesis of ______ is a direct result of decreasing glucose levels.
cAMP
The amino acid tryptophan functions as a(n) _______ in the control circuit of the trp operon.
co-repressor