MCB3020 E2

As the mRNA is synthesized, new nucleotides are added to the 5' end so that the transcript grows in the 3' to 5' direction. True or False

False

The bacteria initiator tRNA is fMet-tRNAiMet whereas the eukaryotic initiator tRNA lacks the formyl group on the amino moiety; Met-tRNAiMet. Archaea, which, like bacteria, lack a nucleus, utilize the same initiator tRNA as bacteria, fMet-tRNAiMet in the initiation of translation. True or False

False

The codon of tRNA is complementary to the anticodon of mRNA. True or False

False

The terminator of a gene is located upstream of the coding region. True or False

False

Regulation of translation initiation by microRNAs and small interfering RNAs is possible since transcription and translation are spatially separated in eukaryotes. This is not the case in bacteria and archaea, where translation begins before transcription has ended. True or False

True

Some degradative pathways are regulated by an activator protein. An activator is a regulatory protein that facilitates transcription by binding to DNA. True or False

True

Eukaryotic ribosomes differ from bacterial ribosomes in that the eukaryotic ribosomes a. Are larger in size and require more initiation factors in order to be positioned properly on the mRNA b. Are larger in size c. Are smaller in size and require more initiation factors in order to be positioned properly on the mRNA d. Are smaller in size and require fewer initiation factors in order to be positioned properly on the mRNA

a. Are larger in size and require more initiation factors in order to be positioned properly on the mRNA

Transposable elements are important factors in the evolution of bacteria because they a. Can transfer antibiotic resistance from one bacterial cell to another b. Allow DNA to become resistant to treatment with UV light c. Can enhance the spread of antibiotic resistance in humans d. Cause lethal mutations in all cases

a. Can transfer antibiotic resistance from one bacterial cell to another

The total number of viable microorganisms remains constant in stationary phase because a. Either there is a balance between cell division and cell death or there is a cessation of cell division even though the cells may remain metabolically active b. There is a balance between cell division and cell death c. None of the choices are correct d. There is a cessation of cell division even though the cells may remain metabolically active

a. Either there is a balance between cell division and cell death or there is a cessation of cell division even though the cells may remain metabolically active

The enzyme that accomplishes transcription is termed _____. a. RNA polymerase b. RNA replicase c. DNA ligase d. RNA ligase e. DNA polymerase

a. RNA polymerase

The reduction of the microbial population to levels that are considered safe by public health standards is called: a. Sanitization b. Antisepsis c. Disinfection d. Sterilization

a. Sanitization

______________ mutations arise occasionally in all cells and in the absence of any added agent. a. Spontaneous b. Triggered c. Planned d. Induced

a. Spontaneous

The __________ is a group of proteins needed for DNA synthesis that assembles at the origin of replication. a. Replisome b. Prospore c. None of the choices are correct d. Septum

a. replisome

Translation is terminated when a stop codon is presented at the ______ site. a. P b. A c. E

b. A

An active repressor protein a. Binds to an inducer to activate it b. Binds to the DNA molecule and prevents transcription c. Binds to the DNA molecule and promotes transcription initiation d. Is a structural protein e. Binds to the RNA polymerase, preventing messenger RNA synthesis

b. Binds to the DNA molecule and prevents transcription

The disinfectant of choice for municipal water supplies is __________. a. either fluorine or chlorine b. Chlorine c. ultraviolet light d. Fluorine

b. Chlorine

Horizontal gene transfer can occur via _________. a. Mitosis b. Conjugation c. binary fission d. Mutation

b. Conjugation

The most effective method by which antibiotic resistance can be decreased in bacteria is a. Increase in vaccination practices b. Decrease in antibiotic use c. Development of new antibiotics

b. Decrease in antibiotic use

7. Organisms that do not require oxygen for growth but grow better in its presence are called: a. Anoxygenic b. Facultative anaerobes c. Aerotolerant d. Microaerophiles

b. Facultative anaerobes

Gamma radiation: a. Has a longer wavelength than UV radiation b. Is used to sterilize some food products c. Is a type of nonionizing radiation d. Has poor penetrating power

b. Is used to sterilize some food products

Sterilization involves ________ all viable microorganisms. a. Removing b. Killing OR removing c. Metabolically inactivating d. Killing

b. Killing OR removing

In eukaryotes, the initiator tRNA for translation is a. ƒMet-tRNAiMet, which is also used by bacteria. b. Met-tRNAiMet, which is also used by archaea. c. Met-tRNAiMet, which is also used by archaea and bacteria. d. different from the initiator used by bacteria and archaea.

b. Met-tRNAiMet, which is also used by archaea.

The method used in horizontal gene transfer is a. Gene splicing b. Nonhomologous recombination c. Mutation d. Crossing over e. Homologous recombination

b. Nonhomologous recombination

The transcription enzyme first attaches to the ______ of the gene. a. Operator b. Promoter c. Initiator d. Coding region e. Regulator

b. Promoter

Transcription is turned off by ______. a. Induction b. Repression c. Induction, repression, and activation d. Activation

b. Repression

Which of the following is the correct order for binary fission? a. A septum forms at mid cell, the cell elongates, replicates its chromosome, and separates the chromosome into the two parts of the cell b. The cell elongates, replicates its chromosome, and separates the chromosome into the two parts of the cell, and a septum forms at mid cell c. None of the choices are correct. d. The cell elongates, a septum forms at mid cell, the cell replicates its chromosome, and separates the chromosome into the two parts of the cell

b. The cell elongates, replicates its chromosome, and separates the chromosome into the two parts of the cell, and a septum forms at mid cell

Bacterial replicons differ from eukaryotic and archaeal replicons in that a. bacteria have no histones and multiple origins of replication, whereas eukaryotes and archaea have a single origin of replication.and their DNA is associated with histones b. bacteria have no histones and a single origin of replication, whereas eukaryotes and archaea have multiple origins of replication.and their DNA is associated with histones c. bacterial DNA is associated with histones and they have multiple origins of replication, whereas eukaryotes and archaea have a single origin of replication.and their DNA is not associated with histones d. bacterial DNA is associated with histones and they have a single origin of replication, whereas eukaryotes and archaea have multiple origins of replication.and their DNA is not associated with histones

b. bacteria have no histones and a single origin of replication, whereas eukaryotes and archaea have multiple origins of replication.and their DNA is associated with histones

Organisms that are not drastically affected by increased pressure are called: a. Osmotolerant b. Barotolerant c. Barophilic d. Osmophilic

b. barotolerant

Organisms that grow near deep-sea volcanic vents are likely to be: a. Psychrophilic b. Thermophilic c. Psychrotrophic d. mesophilic.

b. thermophillic

Which of the following influence(s) the efficiency of an antimicrobial agent? a. Temperature b. Duration of exposure c. All of the choices are correct d. Concentration of the agent

c. All of the choices are correct

Vertical gene transfer is the transfer of DNA a. Between tumor cells b. By crossing over c. During normal cell division d. Between different genomes e. By mutation

c. During normal cell division

The process of forming a cross wall between two daughter cells is known as _______________. a. Mitosis b. Sporulation c. Septation d. Replication

c. Septation

Most bacterial and archaeal cells divide by: a. Mitosis b. Meiosis c. binary fission d. all of these choices are correct

c. binary fission

Horizontal gene transfer is the transfer of DNA a. Between tumor cells b. During normal cell division c. By mutation d. Between different genomes e. By crossing over

d. Between different genomes

When a microorganism such as E. coli is grown on glucose it is a. Incapable of amino acid production b. It is unable to produce its peptidoglycan layer c. Unable to synthesize a cell wall d. Capable of amino acid production e. Unable to produce ATP

d. Capable of amino acid production

The limitation on microbial growth rate at high nutrient levels is/are a. The rate of protein synthesis b. All of the choices are correct c. The rate of DNA replication d. The saturation of the transport proteins for nutrient uptake

d. The saturation of the transport proteins for nutrient uptake

Hfr strains contain the F factor integrated into their ________, rather than in the __________. a. chromosome; mitochondrial DNA b. cytoplasm; chromosome c. chromosome; chloroplast d. chromosome; cytoplasm

d. chromosome; cytoplasm

The two most important alcohol germicides are __________ and __________. a. methanol; isopropanol b. ethanol; methanol c. methanol; butanol d. ethanol; isopropanol

d. ethanol; isopropanol

Which kind of sterilization procedure takes advantage of the size of microorganisms a. Open flame b. Use of chemicals c. Autoclaving d. filtration

d. filtration

Translation is the synthesis of _______. a. Proteins from DNA b. mRNA from DNA c. mRNA from proteins d. Proteins from mRNA e. Proteins from tRNA

d. proteins from mRNA

What event occurs as the ribosome shifts down the mRNA by a distance of three nucleotides? a. The tRNA that was in the P site moves into the A site. b. The tRNA that was in the E site moves into the P site. c. The tRNA that was in the E site moves into the A site. d. The tRNA that was in the A site moves into the E site. e. The tRNA that was in the P site moves into the E site.

e. The tRNA that was in the P site moves into the E site.