exam 3 sb

Your patient is suffering from a urinary tract infection, and the lab has identified three antibiotics that are effective against the causative organism. The therapeutic index of each is listed below. Which one is the best choice?

10

A codon contains how many nucleotides?

3

Treatment of materials to be sterilized with ethylene oxide in a chemiclave requires about _____.

3hr

Which two of the following DNA sequences are palindromic?

5'-AGATCT-3' 5'-GATATC-3'

What is the length of a typical tRNA molecule?

75-95 bases

Which of the following signifies translation termination?

A nonsense codon is reached and the peptide is released from the ribosome

Several Pseudomonas species have been genetically altered creating strains that have which of the following characteristics?

Ability to produce insecticide Inability to form ice crystals

During translation elongation, peptide bonds form between:

Amino acids

Which two of the following statements concerning global transport and the spread of resistant microbes are correct?

An air traveler with drug resistant tuberculosis can spread it on other continents in a short time. Bacterial, viral, fungal and protozoal diseases are all showing an increase in drug resistance worldwide.

Which of the following describe the advantages of creating transgenic animals?

Animals that can make products useful to humans Similarity between animals and humans Animal models to study human diseases Animal models to test new therapies

______ chemotherapy is the use of chemotherapeutic drugs to control infection and diseases caused by many types of microorganisms.

Antimicrobial

Chlorhexidine solutions are commonly used for:

Antisepsis of skin Skin wound care

Which genus of fungi is NOT a major source of antibiotics?

Aspergillus

--- is a narrow-spectrum antibiotic used for superficial skin infections.

Bacitracin

Which of the following is a bacterial cell wall inhibitor found in over-the-counter antibacterial ointments?

Bacitracin

Which statement regarding antibiotics and biofilms is correct?

Bacteria express different genes and exhibit a different phenotype when they are attached to surfaces in a biofilm.

The microbial agents that are least resistant to physical and chemical control methods include:

Bacterial vegetative cells Enveloped viruses

--- are effective cloning vectors because they can transfer donated DNA through transduction.

Bacteriophages

Which two of the following statements are correct regarding the use of bacteriophage to treat infections?

Bacteriophages are specific to a single species of microbe. Bacteriophages have been shown to be active against microbes in biofilms.

RNA can hybridize with --- or ---

Blank 1: DNA or ssDNA Blank 2: RNA

--- --- is the enzyme that can convert RNA into DNA.

Blank 1: Reverse Blank 2: Transcriptase

--- and --- of the foreign gene to make the protein product will occur if a cloning host receives the recombinant plasmid.

Blank 1: Transcription Blank 2: Translation

A — agent will inhibit the growth of bacteria, whereas a — agent will kill bacteria.

Blank 1: bacteristatic or bacteriostatic Blank 2: bactericidal or bactericide

An organism that receives and replicates a foreign piece of DNA inserted during a genetic engineering experiment is called the

Blank 1: cloning Blank 2: host

The three methods of gene transfer in bacteria are , , and .

Blank 1: conjugation Blank 2: transformation Blank 3: transduction

A --- --- is an enzyme present naturally in cells that cleaves specific locations on DNA.

Blank 1: restriction Blank 2: enzyme

The pieces of DNA produced by restriction endonucleases are termed .

Blank 1: restriction Blank 2: fragments

The pentose sugar in RNA is , while in DNA the pentose sugar is .

Blank 1: ribose Blank 2: deoxyribose

Fill in the blank question. One reason protein synthesis is more efficient in bacteria than in eukaryotes because bacterial and are simultaneous.

Blank 1: transcription Blank 2: translation

One approach to controlling bacteria and fungi is by --- the synthesis of the cell wall.

Blocking

Which three are examples of using moist heat to sterilize or disinfect materials?

Boiling Autoclaving Pasteurization

Which of the following drugs are linked to the development of superinfection?

Cephalosporin Tetracyclines Penicillin

Which of the following are effects of ionizing radiation on food products?

Changes in texture of some foods Killing of bacterial pathogens Small decreases in thiamine

In this Kirby Bauer test performed on E. coli, the bacterium is resistant to:

Chloramphenicol Oxytetracycline

Ethylene oxide, propylene oxide and --- dioxide are commonly used as gaseous sterilants or disinfectants.

Chlorine

A critical concern for the food packaging industry is the elimination of endospores of

Clostridium botulinum

What is the primary intent of recombinant DNA technology?

Combine genetic material from two organisms

What is used in the laboratory to renature DNA into its normal double stranded form?

Cooling

There are thousands of different restriction enzymes that each cut --- at a different sequence.

DNA

Which cellular component is damaged by UV radiation?

DNA

RNA can hybridize with ______.

DNA and RNA

What is the central dogma hypothesis of genetics?

DNA encodes RNA which encodes protein

Which two of the following statements are correct regarding DNA replication elongation?

DNA polymerase I removes the RNA primers used to initiate DNA synthesis. Replication proceeds at a rate of 750 bases per second.

In regard to DNA replication elongation, which two statements are correct?

DNA polymerase I removes the RNA primers used to initiation synthesis. DNA ligase joins the lagging strand fragments.

What are the main effects of ionizing radiation on cellular targets?

Damage to proteins Chemical changes in organelles

Alcohol is used in which of the following applications?

Degermation of skin

Alcohols, acids, and phenolics have which effect on proteins?

Denature

Which three strategies can be used to isolate a target gene for use in recombinant DNA technology?

Digestion with endonucleases Amplification by PCR Synthesis of cDNA

Select the statement that most accurately reflects the use of heat as an antimicrobial agent.

Dry heat methods exert their effect by dehydrating cells.

Which is true regarding DNA replication?

Each new DNA helix contains one parent strand and one newly synthesized strand.

Which enzyme cleaves specific locations on DNA to produce fragments that are used to splice genes in genetic engineering?

Endonuclease Reason: Helicase unwinds DNA. Reason: Ligase seals sticky ends. Reason: DNA polymerase adds complementary nucleotides during replication.

Viruses, prions and --- are relatively resistant to heat.

Endospores

Which of the following are not usually destroyed or inactivated with regular pasteurization methods?

Endospores Thermophilic microbes

Which of the following are used to visualize probes that have hybridized with the test sample?

Enzymes Fluorescent dyes Luminescent labels

Which two alcohols are effective in microbial control?

Ethyl Isopropyl

Which of the following compounds are commonly used as gaseous sterilants or disinfectants?

Ethylene oxide Chlorine dioxide Propylene oxide

To adequately sterilize using heat, temperature and length of --- must be considered.

Exposure

The final step of PCR is known as ---, and involves the synthesis of complete complementary strands of DNA.

Extension

Which step of PCR involves the synthesis of complete complementary strands of DNA?

Extension

True or false: A process that completely removes or destroys all viable microorganisms, including viruses, from an object or habitat is referred to as disinfection.

False

True or false: Fluoroquinolones only inhibit gram-negative bacteria.

False

True or false: Operons are found in fungi and helminths.

False

True or false: Plasmids are insertion sequences that can lead to changes in genotype within a cell or between cells.

False Reason: Insertion sequences that can lead to changes in genotype within a cell or between cells are called transposons. Plasmids are small circular pieces of DNA.

True or false: Sterilization methods are often used to prepare the human body for surgical procedures.

False Reason: Sterilization is generally reserved for inanimate objects and would be harsh on body tissues.

True or false: 100% alcohol solutions have greater microbicidal activity than 70% solutions.

False (Reason: Because water is necessary to their action on proteins, a lower concentration of alcohol is more effective.)

True or false: Incineration is an example of using moist heat to sterilize or disinfect materials.

False (Reason: Incineration is an example of dry heat.)

True or false: Dessication is a method for preserving microorganisms (and other substances) by freezing and then drying them directly from the frozen state.

False (Reason: Lyophilization is the method of freezing and drying.)

True or false: Routine skin antisepsis often is completed using phenolics.

False (Reason: Phenolics may be very irritating to the skin.)

True or false: Biological matter such as serum, blood or urine increases the effectiveness of a germicide.

False (Reason: These hinder the penetration and activity of the germicide.)

--- dyes are used to visualize probes that have hybridized with the test sample.

Fluorescent

Acids and alkalis are commonly used for:

Food preservation Household cleaning

Which two of the following statements concerning global transport and the spread of resistant microbes are correct?

Food products often carry microbes from their place of origin. Global travel means that drug resistance can spread rapidly.

--- is an aqueous solution of formaldehyde gas that is used as a potent chemical fixative and microbicide.

Formalin

Which type of mutation is generally most harmful to cells?

Frameshift mutation

Sterilization is:

Generally reserved for inanimate objects Only necessary for certain groups of microbes

Which of the following are NOT primary sites for action of antimicrobial drugs in bacteria?

Golgi apparatus (bodies) Mitochondria

Which of these restriction endonucleases will cut DNA but not leave sticky ends?

HaeIII

Which level of chemical decontamination by a germicide can result in sterilization?

High level

Which of the following are desirable characteristics in a good cloning host?

High yield of proteins Nonpathogenic Rapid growth rate Can accept foreign DNA Mapped genome

Which of these restriction endonucleases will cut DNA and leave sticky ends?

HindIII EcoRI

How are phenolics used in microbial control?

Household disinfection Added to products Clinical disinfection

Plasmolysis of bacteria in foods occurs when high concentrations of salt or sugar are added to the foods creating a --- environment.

Hypertonic

Which three of the following are examples of disinfection?

Immersing thermometers in an iodine solution A 5% solution of bleach to clean a lab table Boiling eating utensils

Which of the following is the practical definition of microbial death?

Inability to reproduce

Heavy metals typically kills microbes by:

Inactivating proteins

What is the importance of PCR?

Increases the amount of DNA in a sample

Which of the following are general mechanisms of antimicrobial drug actions?

Inhibiting cell wall synthesis Inhibiting nucleic acid structure or function Inhibiting protein synthesis Interference of cell membrane structure and function

Which of the following is NOT a general mechanism of antimicrobial drug actions?

Inhibiting electron transport systems

--- is a normal human glycoprotein produced in response to immune stimuli and can be used therapeutically to fight viruses and cancer.

Interferon

______ is a normal human glycoprotein produced in response to immune stimuli and can be used therapeutically to fight viruses and cancer.

Interferon

_____ is a good technique for sterilizing materials that are sensitive to heat or chemicals.

Ionizing radiation

What is the main disadvantage of using E. coli as a cloning host?

It cannot process mRNA transcripts from eukaryotes.

What is the function of mRNA?

It carries a copy of a DNA sequence to the ribosome.

The --- technique is an agar diffusion test to determine antibiotic susceptibility of a particular bacterial strain.

Kirby-Bauer

Which strand is replicated discontinuously in segments during DNA replication?

Lagging

Which strand is replicated continuously without segments during DNA replication?

Leading

Select the enzymes that function in DNA replication.

Ligase DNA polymerase Helicase

Cloning hosts commonly used in recombinant DNA technology include:

Live animals and plants Yeasts Animal cell cultures Several bacterial species

What is the first challenge in the recombinant DNA process in cloning a target gene?

Locating and isolating a target gene

Which two of the following statements regarding multidrug resistance (MDR) pumps are correct?

MDR pumps are encoded by genes on plasmids. MDR pumps work by active transport.

Which of the following is NOT a way that a chemical control agent damages a cell wall?

Making it more permeable (leaky)

Which two of the following statements regarding plasmids are true?

Many bacteria carry plasmids in addition to their chromosome. Plasmids may contain genes that specify resistance to antibiotics.

Younger, active cells die more quickly when exposed to microbicidal agents because they are more --- active.

Metabolically

--- can silence gene expression, making these molecules valuable in the study of disease and the development for potential therapeutic treatments.

Micro RNA, miRNA, miRNAs, or Micro RNAs

Which three factors have the greatest influence on the action of antimicrobial agents?

Microbial load Temperature of environment Presence of interfering matter

The lowest concentration of a drug that visibly inhibits growth is called the --- , or MIC.

Minimum inhibitory concentration

In terms of using heat as an agent of microbial control, --- heat methods operate at lower temperatures and shorter exposure time versus --- heat methods.

Moist ; Dry

Which of the following semisynthetic penicillins are useful in treating infections caused by penicillinase-producing bacteria?

Nafcillin Cloxacillin

The effect of a germicide is affected by which of the following factors?

Nature of microbial population Chemical action of germicide Material being treated Time of exposure to germicide Concentration of germicide Contamination with organic matter

What is the result of a point mutation that changes a template gene sequence from 3'-TACGCCATATAT-5' to 3'-TACGCCATCTAT-5'?

Nonsense mutation

Which two factors contribute to the spread of antibiotic resistances genes in the hospital environment?

Not all hospital workers follow infection control guidelines. Many hospital patients have weakened defenses.

Which of the following are disadvantages of OPA as a disinfectant?

OPA does not reliably destroy endospores. It tends to stain proteins, including those in human skin.

Which of the following statements are correct regarding OPA?

OPA is an aldehyde. OPA is non-irritating to eyes and nasal passages.

During DNA replication, the lagging strand is replicated in a discontinuous manner forming fragments.

Okazaki

The property of having antimicrobial effects in exceedingly small amounts is called a(n) _____ action.

Oligodynamic

Which best describes the antiparallel orientation of strands in DNA?

One strand is 5' to 3' and the other is 3' to 5'.

In bacteria, a regulatory gene, a control region, and structural genes collectively are referred to as a(n)

Operon

Which operational unit in bacteria consists of a regulatory gene, a control region, and structural genes?

Operon

A mutation that affects only a single base pair in DNA is termed a(n) mutation.

POINT

Which antibiotic does NOT target transcription or translation in bacteria?

Penicillin

Endoscopy equipment becomes highly contaminated with human tissues and fluids, and should be sterilized in a low-temperature cabinet using which sterilants?

Peracetic acid Hydrogen peroxide

Select the statements that reflects problems that have led to the worldwide problem of managing antimicrobial drugs.

Physicians use a "shotgun" approach to treat minor infections Many prescriptions are given to control upper respiratory infections typically caused by viruses Drugs are prescribed without susceptibility testing

Which of the following is a type of mutation that affects only a single base pair in DNA?

Point

Which of the following materials can not be autoclaved?

Powders Oils and waxes Heat-sensitive plastic

What factors must be considered in order to adequately sterilize using heat?

Presence of water Length of exposure Temperature

Identify the three major modes of action of antiviral drugs.

Preventing virus maturation Blocking virus transcription and translation Barring virus penetration into host cell

What are the main effects of antimicrobial agents on DNA?

Prevention of replication Permanent mutations

Which enzyme synthesizes primer sequences during replication initiation?

Primase

--- are short strands of a known sequence of DNA that serve as landmarks to indicate where DNA amplification will begin in PCR.

Primers

--- the second step of PCR, involves the hybridization of the target DNA and short complementary sequences to initiate synthesis.

Priming

Which step of PCR involves the hybridization of the target DNA and short complementary sequences to initiate synthesis?

Priming

______ are preparations of live microbes used as a preventive or therapeutic measure to displace or compete with potential pathogens.

Probiotics

Which two of the following statements about probiotics are correct?

Probiotics can be found easily in grocery stores. Probiotics are safe for the general population to consume.

This gas is safer to use than ethylene oxide to sterilize food products, such as starches, spices, and nuts.

Propylene oxide

What is the role of restriction endonucleases in a living bacterium?

Protecting against foreign DNA

Which three of the following events in protein synthesis occur post-translationally?

Protein folding Removal of the formyl methionine Addition of cofactor

Which process in bacteria do the antibiotics in the group including erythromycin and spectinomycin specifically inhibit?

Protein synthesis

The four general cellular targets of antimicrobial agents are the cell wall, the cell membrane, nucleic acid synthesis, and ---

Proteins

Which two of the following can be produced by recombinant DNA technology?

Proteins Nucleic acids

Which of the following are NOT characteristics of the ideal antimicrobial drug?

Purified from organically grown ingredients Replaces host's own defenses

In the central dogma, DNA encodes which encodes protein.

RNA

PCR can be modified today for the analysis of --- by using reverse transcriptase to convert the nucleic acid sample to a DNA form.

RNA

The antibiotic rifamycin, used to treat tuberculosis, binds and inhibits the activity of

RNA polymerase

Which is the main event of transcription initiation?

RNA polymerase binds the DNA promoter

Which of the following occurs during transcription termination?

RNA polymerase reaches a terminator region.

Which form of PCR can be used to detect gene products during the actual PCR cycle itself, making microbial identification very rapid and sensitive?

Real-time PCR

Which two of the following statements regarding recombinant DNA technology are correct?

Recombinant DNA technology can be used to manufacture proteins. Recombinant DNA technology can be used to manufacture medications.

Which of the following are primary sites for action of antimicrobial drugs in bacteria?

Ribosomes Cell wall Nucleic acids Cell membrane

Which strategy is not used to isolate a target gene for use in recombinant DNA technology?

Sanger method DNA sequencing

Which of the following heavy metals are still used in germicidal preparations?

Silver Mercury

What property of a DNA fragment determines the distance it moves during gel electrophoresis?

Size of fragment

Which two of the following statements regarding eukaryotic transcription and RNA processing are correct?

Splicing to remove introns occurs in the nucleus. A series of adenosines is added to the mRNA.

Filtration has been used in which of the following?

Sterilization of medical products Decontamination of air Water purification Decontamination of milk products

The two major bacterial sources of antibiotics are the genera --- and ---.

Streptomyces Bacillus

Which kind of gene encodes a protein?

Structural

Resistance to which of the following drugs develops when microbes deviate from the usual pathway that leads to the production of folic acid?

Sulfonamides Trimethoprim

A --- is an agent that disrupts the lipid bilayer of membranes and alters the membrane's permeability.

Surfactant

What is the importance of cDNA?

Synthesis of eukaryotic genes without introns

Which two statements about DNA replication in bacteria and eukaryotes are correct?

Telomere DNA gets progressively shorter with each copy. Eukaryotes initiate replication from multiple origins of replication.

Glycylcyclines are newer derivatives of _______.

Tetracyclines

What determines the order of amino acids in the primary structure of a protein?

The DNA sequence of a gene

The four general cellular targets of antimicrobial agents are ....

The cell wall Protein function Nucleic acid synthesis The cell membrane

Which two statements regarding eukaryotic transcription and RNA processing are correct?

The exon-intron junction is recognized by a spliceosome. Transcription occurs before splicing.

Which two of the following statements regarding tRNA structure are correct?

The overall structure is termed a cloverleaf. tRNA has regions that are double-stranded RNA.

Why is it difficult to achieve selective toxicity when developing antiviral drugs?

The virus and host use the same metabolic system for their well-being.

Why are plasmids effective vectors in recombinant DNA technology?

They can be manipulated easily. They are well characterized. They can be transferred through transformation.

Why is PCR conducted at high temperatures?

To keep the DNA strands separated

What is a major side effect of tetracyclines?

Tooth discoloration

Which two of the following statements comparing DNA replication in bacteria and eukaryotes are correct?

Topoisomerases relieve the superhelical tension as DNA is replicated. Eukaryotic DNA is linear whereas bacterial DNA is circular.

Once a cloning host receives the recombinant plasmid in recombinant DNA technology, what will it do with the plasmid?

Transcribe and translate the foreign gene to make protein

Which gene transfer method involves the uptake of free DNA by competent bacterial cells?

Transformation

Select the types of horizontal gene transfer that can allow for bacteria to acquire antibiotic resistance genes.

Transformation Transduction Conjugation Transposition

The uptake of free DNA by competent bacterial cells occurs during bacterial

Transformation.

Insertion sequences that can lead to changes in genotype within a cell or between cells are called "jumping genes" or

Transposons

Scientists have demonstrated --- resistance found in organisms, such as E. coli, leads to antibiotic resistance by these organisms.

Triclosan

The use of waters containing this phenolic for irrigation may lead to the evolution of microorganisms that are resistant to it and other antimicrobials that end up in our food supply.

Triclosan

True or false: Many copies of a specific protein can be synthesized from a single mRNA transcript in a polyribosomal complex.

True

True or false: Ribose is the pentose sugar in RNA.

True

True or false: Synthetic biology occurs when researchers try to make organisms from scratch.

True

True or false: The anticodon for the codon 5'-AUG-3' is 3'-UAC-5'.

True

True or false: The primary targets of microbial control are microorganisms that cause infection or spoilage.

True

True or false: The two primary iodine preparations are free iodine and iodophors.

True (Reason: Iodophors are a combination of iodine and an organic carrier such as alcohol.)

True or false: Cold treatment and desiccation cannot be reliably used for sterilization or disinfection.

True (Reason: One cannot be sure pathogens have been killed since these methods are uncertain.)

Which of the following microbial forms are relatively resistant to heat?

Viruses Endospores

The structure of DNA was discovered in 1953 by

Watson and Crick

Which of the following are types of ionizing radiation?

X-rays Gamma rays

Most bacterial plasmids carry an origin of replication and at most Blank______ genes.

a few dozen

The biosynthesis of the amino acid histidine requires several enzymes whose genes are organized in the his operon. The his operon would be expected to be active when the cell is growing in a medium containing Blank______.

a low concentration of amino acids

The main benefit of gene therapy is:

a permanent cure for a disease

The regulator of the lac operon is a gene that encodes

a repressor protein

The arginine operon is "on" when the cell is

actively growing

Patients taking penicillin may experience --- reactions.

allergic

A major problem for treatment with penicillin is that some patients experience

allergic responses

The lactose repressor protein ihas two binding sites, one for the operator DNA sequence and another for lactose, the presence of two binding sites means that it is

allosteric

Primers are short strands of a known sequence of DNA that serve as landmarks to indicate where DNA --- will begin in PCR.

amplification

Nucleotide is to nucleic acid as is to protein.

animo acid

The Kirby-Bauer technique is an agar diffusion test to determine --- susceptibility of a particular bacterial strain.

antibiotic

In DNA, the two strands of the helix are arranged in a(n) orientation

antiparallel

Which microbial agent is the most resistant to physical and chemical control methods?

bacterial endospores

a ______ is an enzyme secreted by certain bacteria that cleaves the beta-lactam ring of penicillin and cephalosporin and thus provides for resistance against the antibiotic. (Choose two.)

beta-lactamase penicillinase

A --- is an enzyme secreted by certain bacteria that cleaves the beta-lactam ring of penicillin and cephalosporin and thus provides for resistance against the antibiotic.

beta-lactamase or penicillinase

Metallic ions have which effect on proteins?

bind to the active site

Binding of arginine to the arginine repressor protein causes the repressor to

bind to the operator sequence

Sodium hypochlorite is also known as

bleach

Fluoroquinolones are - ---spectrum drugs.

broad

If a particular antimicrobial drug is effective against a variety of different bacteria, it would have a ______ spectrum.

broad

Organisms resistant to penicillins and --- often produce beta-lactamases that hydrolyze the beta-lactam ring structure of the antibiotic.

cephalosporins.

Antiseptics are ______ agents applied to the skin to inhibit vegetative bacterial cells.

chemical

The specific sequence of three mRNA nucleotides, based on a DNA triplet, that encodes a particular amino acid, is a(n)

codon

DNA that is made from RNA is called --- dna

complementary

A recombinant is defined as an organism that

contains and expresses genes that originated in another organism

The main benefit of gene therapy is the permanent --- for a disease.

cure

Gene probes are commonly used for ______.

diagnosing causative agents of infection identifying bacteria or viruses in an unknown culture

Ensuring that the DNA code will be maintained during cell growth and cell is one of the two essential effects of the structure of DNA.

division

Watson and Crick discovered the structure of DNA in 1953, and described it as a(n)

double helix

The production of beta-lactamases is responsible for

drug inactivation

--- --- is where microbes begin to tolerate an antimicrobial agent at a level which would normally be inhibitory.

drug resistance

High-level germicides can kill ---, whereas intermediate-level germicides can kill fungal spores and resistant pathogens but not endospores.

endospores or bacterial endospores

The gas --- --- is used to sterilize prepackaged medical devices, syringes, and Petri dishes.

ethylene ; oxide

Antifungal agents are often toxic to host cells because the fungal and the host cells are both ---

eukaryote

The main disadvantage of using E. coli as a cloning host is the inability of the bacterium to process mRNA transcripts from --- due to the presence of introns.

eukaryotes

The effect of a germicide is affected by the time of

exposure

True or false: A good cloning host should be pathogenic.

false

True or false: Household cleaners are often alcohol based.

false

True or false: Ionizing radiation is not an effective method of controlling microbes in food products.

false

True or false: Okazaki fragments are formed during DNA replication of the leading strand.

false

True or false: The effectiveness of an antimicrobial agent is only governed by the time of exposure to the agent?

false

True or false: In the laboratory, DNA loses many of its normal properties.

false Reason: All of the intrinsic properties hold true whether in lab or natural host cell.

True or false: A DNA copy that is made from RNA is called recombinant DNA.

false Reason: Recombinant DNA is made when the DNA from one organism is combined with the DNA of another organism.

True or false: Quinolones may cause liver and kidney damage, as well as hearing loss.

false Reason: Seizures and brain disturbances occur as side effects of quinolones.

True or false: Drugs that are selectively toxic kill the host cells without harming the microbial cells.

false Reason: Selective toxicity refers to killing the microbe without harming the host.

True or false: The most effective drugs that treat infections caused by flukes, tapeworms, and roundworms eradicate the adult stages of the organisms.

false Reason: They typically block metabolism at all stages of the life cycle rather than eradicate the adult worms.

True or false: Humans make good cloning hosts.

false Reason: Bacteria and yeast are two examples of good cloning hosts.

True or false: Reasonable price should not be a factor in selecting an ideal antimicrobial drug, as long as it is effective.

false Reason: If multiple drugs are effective, the most reasonably priced drug would be most ideal.

True or false: The minimum inhibitory concentration is the lowest dilution of a drug where it visibly inhibits growth of a particular microorganism.

false Reason: It is the highest dilution (smallest concentration) of the drug

The use of --- ---, or the transfer of feces containing beneficial normal biota from healthy patients, has been shown to be therapeutic in some cases of C. difficile infection.

fecal transplant

Resistance to sulfonamides and trimethoprim develops when microbes use an alternative pathway for --- acid synthesis.

folic

The primary targets of microbial control are microorganisms that cause ______ or ______.

food spoilage and disease

The CRISPR areas of the bacterial genome are capable of recognizing and cutting _____ DNA.

foreign

Mutations that are generally most harmful to cells because they cause the greatest change in the amino acid sequence of a protein by change the reading frame of the mRNA are called mutations.

frameshift

--- --- is a laboratory technique for separating DNA fragments according to length by employing electricity to force the DNA through a gel-like matrix.

gel electrophoresis

involves the introduction of normal functional genes into cells of people with genetic diseases such as sickle cell anemia and cystic fibrosis.

gene therapy

Random fragments of host DNA are taken up by the bacteriophage during assembly in Blank______ transduction.

generalized

Recombinant organisms produced through the introduction of foreign genes are called transgenic or

genetically modified organism

Sepsis is defined as

growth of microorganisms in the blood or other tissues

Which of the following is used in the laboratory to separate strands of DNA?

heat

Ionizing radiation is a good technique for sterilizing materials that are sensitive to --- or ---

heat, heating, or temperature ; chemicals or chemical

The property of having antimicrobial effects in exceedingly small amounts belongs to which class of chemicals?

heavy metals

In DNA replication, unwinds (unzips) the double helix, primase synthesizes the short RNA primer, and DNA adds nucleotides to the new chain.

helicase polymerase

Your patient is suffering from pneumonia, and the lab has identified two antibiotics that are effective against the causative organism. Based on therapeutic index (TI), which is the better choice?

high TI (bigger ratio)

____ concentrations of alcohol may not have the greatest microbicidal activity, for water is needed for microbial proteins to coagulate.

higher

Various forms of --- ---, such as transformation, transduction, or conjugation, appear to allow for rapid proliferation of drug-resistant microbes.

horizontal transfer

Viruses are infectious agents that require a --- in order to complete their life cycle.

host

Sterilization methods are usually reserved for

inanimate objects

PCR --- the amount of DNA in a sample over a short period of time.

increases, amplifies, or multiplies

Because lactose is ultimately responsible for stimulating protein synthesis from the lac operon, it is called the

inducer

The binding of arginine to the arginine repressor protein causes the repressor to bind to the operator region. This happens because arginine

induces a conformational change in the protein

The binding of lactose to the lactose repressor protein causes the repressor to leave the operator region. This happens because lactose

induces a conformational change in the protein

Many catabolic operons are Blank______, while those that encode anabolic enzymes are Blank______. Multiple choice question.

inducible; repressible

What is the mode of action of erythromycin?

inhibits protein synthesis

The gene called "ori" in this cloning vector functions to ______.

initiate plasmid replication

Several Pseudomonas species have been genetically altered creating strains that protect plants from pests by producing

insecticides

The advantage of cDNA in genetic engineering is the synthesis of eukaryotic genes without

introns

Sterilization of the skin:

is highly dangerous and impractical

Polymyxin B and E are toxic to the

kidney

Polymyxin B and E are toxic to the body's ______.

kidneys

Which molecule is the inducer of the lac operon?

lactose

In the lac operon the binds to the operator.

lactose repressor

In the gel seen here, DNA was loaded in wells at the top. Bands near the top would be relatively ______.

large

Binding of lactose to the lactose repressor protein causes the repressor to

leave the operator sequence

What enzyme rejoins the phosphodiester bonds at the sticky ends of DNA?

ligase

Filtration is used to prepare --- that cannot be heated, and to remove --- contaminants that are a common source of infection and spoilage.

liquids or fluids ; airborne

A copy of the DNA template corresponding to a protein-encoding gene is

mRNA

During translation initiation, the ribosome binds to the RNA transcript.

messenger

The most effective drugs used to treat infections caused by flukes, tapeworms, and inhibit --- at all stages of the helminthic life cycle rather than eradicating the adult worms themselves.

metabolism

Which type of molecule can silence gene expression, and whose levels can be modified in order to treat disease expression?

miRNA

Many bacteria possess --- that actively transport drugs out of the cells.

multidrug resistant (MDR) pumps

The region indicated by the arrow in this cloning vector is the ______. (mcs)

multiple cloning site

An agent that induces changes in DNA is a(n)

mutagen

A small number of are considered beneficial in that they provide the cell with a useful change in structure or physiology. Antibiotic resistance in bacteria is an example.

mutations

The main effects of antimicrobial agents in DNA are permanent --- and the prevention of ---

mutations ; replication

An antimicrobial that is effective against a limited array of microbial types is called a --- spectrum drug.

narrow

Bacteriophages can be considered a _____-spectrum antimicrobial treatment.

narrow

If an antimicrobial drug is only effective against gram-negative bacteria, it has a(n) ______ spectrum.

narrow

The major side effects of quinolones involve the ______ system.

nervous

Early termination of the protein is the result of a Blank______ mutation.

nonsense

In somatic cell gene therapy, the change introduced into the genome is (choose two)

not passed to the individual's offspring present in every cell of the individual

Building blocks of DNA, called , contain the same sugar and phosphate, but different nitrogenous bases.

nucleotides

When a cell is actively growing, the arg operon is Blank______, and arginine is Blank______.

on; actively synthesized

The control locus of the lac operon contains a region of DNA that acts as an on/off switch for transcription called a(n) Blank______.

operator

The lactose repressor protein binds to the Blank______ of the lac operon.

operator

The gene called "ori" in this cloning vector is the ______.

origin of replication

In this figure showing a Kirby-Bauer assay performed on a lawn of E. coli, the bacterium is resistant to chloramphenicol and --- while it displays sensitivity to enrofloxacin and ---.

oxytetracycline cefotaxime

--- requires cyclic repetition of denaturation, priming, and extension in order to amplify the DNA.

pcr

Methicillin, cloxacillin, and nafcillin are useful in treating infections caused by - ---producing bacteria.

penicillinase or beta-lactamase

Bacteria "learn" the identity of an attacking phage by

placing bits of phage DNA in its own genome

--- are good cloning vectors because they may be transferred into appropriate host cells through transformation.

plasmid

A fragment of DNA with the wild type sequence 5'-AGCTGACGACCAGGTGACCAG-3' is found in a mutant to be 5'-AGCTGAGGACCAGGTGACCAG-3'. The term that best describes this mutation is Blank______.

point mutation

dna. is the enzyme that synthesizes DNA strands in the 5' to 3' direction.

polymerase

Each member of a species will produce restriction fragments of differing lengths due to variations in DNA sequences. This is referred to as restriction fragment length

polymorphism

In gel electrophoresis, DNA moves towards the ______ pole in the gel.

positive

"Finishing touches" on proteins are termed Blank______ modification. Multiple choice question.

posttranslational

--- are nutrients used to stimulate the growth of favorable biota in the intestine.

prebiotics

In germline gene therapy, the change introduced into the genome is (choose two)

present in every cell of the individual passed to the individual's offspring

During replication, the enzyme synthesizes primer sequences.

primase

A gene --- can be used for identifying bacteria or viruses in an unknown culture and diagnosing causative agents of infection.

probe

Fecal transplants represent an adapted use of:

probiotics

Protein synthesis is more efficient in prokaryotes than in eukaryotes for all of the following reasons except

prokaryotic ribosomes are 70S rather than 80S

RNA polymerase binds to the region of the DNA to initiate transcription.

promoter

The control locus of the lac operon is composed of the Blank______, a region of DNA that is recognized by RNA polymerase.

promoter

During protein synthesis, many copies of a specific can be synthesized from a single mRNA transcript in a polyribosomal complex.

protein

Erythromycin inhibits synthesis.

protein

Tetracycline inhibits --- synthesis.

protein

Tetracyclines inhibit

protein synthesis

The region indicated by the arrow on this cloning vector functions to ______. (mcs)

provide a series of restriction sites

UV radiation causes the formation of abnormal linkages in DNA known as

pyrimidine ; dimers

An organism that contains and expresses genes that originated in another organism is called a

recombinant

The primary intent of --- DNA technology is to combine the genetic material from two organisms.

recombinant

The _____ of the lac operon is a gene that encodes a repressor protein.

regulator

Glycylcyclines bind to the 30S --- subunit and block entry of the tRNA.

ribosome

Most drugs that inhibit protein synthesis or translation block the action of the 30S or 50S subunits of the ---

ribosome

Protein synthesis - inhibiting drugs, such as streptomycin, affect the action of the cell's ______.

ribosomes

The property of an antimicrobial agent to be highly toxic against its target microbe while being far less toxic to the cells of the host organism is called --- toxicity.

selective

Antibiotic drugs put a --- pressure on the bacteria which allow the more "fit" microbes to --- and multiply.

selective survive

During DNA replication the newly made double helices are composed of one parent template and one newly synthesized strand and therefore the replication is considered

semiconservative

The fusion of a natural microbial product with a preselected molecule results in the formation of a(n) _____ antibiotic.

semisynthetic

is defined as growth of microorganisms in the blood or other tissues.

sepsis

The following sequence is found at the beginning of a gene in the wild type: 5'-ATGCCAGGTCGTACA-3'. In a related strain of bacteria, the sequence is 5'-ATGCCCGGTCGTACA-3'. Since the codons CCA and CCC both encode proline, this mutation is best described as a _____ mutation.

silent

One advantage of using transgenic animals is the ---between animals and humans.

similarity

The --- of a DNA fragment determines the distance it moves during gel electrophoresis.

size/length

In the gel shown, DNA was loaded in wells at the top. Bands near the bottom would represent relatively ______ fragments of DNA.

small

A particular part of the host genome is included in the virus during Blank______ transduction.

specialized

agent can also be a sterilant because it can destroy bacterial endospores and leave an object free of all life.

sporicidal or sporicide

A process that completely removes or destroys all viable microorganisms, including viruses, from an object or habitat is referred to as

sterilization

Because of concerns about botulism, commercial food canneries must _____ food items.

sterilize

After using a disposable plastic item like a catheter, it should be ---

sterilized by any convenient method before disposal

DNA segments that code for proteins are referred to as genes.

structural

DNA segments that code for proteins are referred to as

structural genes

A(n) --- is an infection occurring during antimicrobial therapy that is caused by an overgrowth of drug-resistant microorganisms.

superinfection

Trimethoprim and sulfamethoxazole are often given in combination because --- of the effect of the two drugs.

synergistic

The field that involves engineering organisms with new capabilities is known as --- biology

synthetic

Amphotericin B is one of the few drugs that can be injected to treat --- fungal infections such as cryptococcus meningitis.

systemic

True or false: During DNA replication, both the leading and lagging strands are synthesized in the 5' to 3' direction.

t

High --- is used during PCR to keep the DNA strands separated.

temperature

In a DNA molecule the parent strands are used as a(n) templateBlank 1Blank 1 template , Correct Unavailable to synthesize a complementary strand of DNA.

template

The process of transcription Blank______ results in the release of a completed RNA transcript.

termination

The antibiotic rifamycin can be used to treat tuberculosis because

the drug is more active against bacterial RNA polymerase than the human enzyme

The lactose repressor protein is allosteric, meaning that it has two binding sites, one for Blank______ and another for Blank______.

the operator DNA sequence lactose

The different types of nucleotides in DNA contain

the same sugar and phosphate, but different nitrogenous bases

DNA polymerases purified from _____ organisms are used in PCR because they remain active at the high temperatures needed to denature DNA

thermophilic

The most significant reason that bacteria in a biofilm are much less susceptible to antibiotics is that ______.

they express different genes than free-living bacteria

Trimethoprim and sulfamethoxazole are often given in combination to exploit the synergistic effect of the two drugs. They are synergistic because

they inhibit two enzymes in the same pathway

DNA polymerases purified from thermophilic organisms are used in PCR because ______.

they remain active at the high temperatures needed to denature DNA

In the image, the electrodes should be placed with the negative electrode at the ______ and the positive electrode at the ______.

top; bottom negative --> positive larger --> smaller

The process of introducing foreign genes to a plant cell by adding the DNA directly to the cell medium is termed

transfection

The process of introducing foreign genes to a yeast cell by adding the DNA directly to the cell medium is termed

transfection

Recombinant organisms produced through the introduction of foreign genes are called --- or genetically modified organisms (GMOs).

transgenic

True or false: A surfactant is an agent that disrupts the lipid bilayer of membranes and alters the membrane's permeability.

true

True or false: Anaphylaxis is the pronounced allergic reaction to antigen that leads to severe respiratory and cardiac complications.

true

True or false: Antiviral drugs prevent penetration, block transcription and translation, and prevent maturation of viral particles.

true

True or false: Chlorhexidine solutions are commonly used for skin antisepsis and wound care.

true

True or false: Drug resistance is where microbes begin to tolerate an antimicrobial agent at a level which would normally be inhibitory.

true

True or false: Drugs that are effective against fungi have a strong possibility of being toxic to humans because both organisms are eukaryotes.

true

True or false: Gel electrophoresis is a laboratory technique for separating DNA fragments according to length by employing electricity to force the DNA through a gel-like matrix.

true

True or false: Gene therapy involves the introduction of normal functional genes into people with genetic diseases such as sickle cell anemia and cystic fibrosis.

true

True or false: Glutaraldehyde and formaldehyde are two of the most frequently used aldehydes.

true

True or false: Ionizing radiation causes damage to proteins.

true

True or false: Reverse transcriptase is the enzyme that can convert RNA into DNA.

true

True or false: Silver and mercury are still used in germicidal preparations.

true

True or false: The 3 steps of PCR are repeated over and over to generate copies of the DNA.

true

True or false: The lowest temperature that achieves sterilization in a given quantity of broth culture upon a 10-minute exposure is referred to as the thermal death point.

true

True or false: The parent strands in a DNA molecule are used as templates to synthesize complementary strands of DNA.

true

True or false: The pieces of DNA produced by restriction endonucleases are termed restriction fragments.

true

True or false: The structure of DNA is essential for providing variety since the order of nucleotides is responsible for the unique qualities of each organism.

true

True or false: The three components that should exist in a vector are an origin of replication, drug resistance gene and space for foreign DNA.

true

True or false: Tooth discoloration is a side effect of tetracyclines.

true

True or false: When their DNA is exposed to a restriction endonuclease, each member of a species will experience different DNA cutting patterns due to different sequences. This is referred to as restriction fragment length polymorphisms.

true

True or false: The organism that receives and replicates a foreign piece of DNA inserted during a genetic engineering experiment is referred to as the cloning host.

true Reason: Cloning hosts must receive the vector in order to replicate the gene of interest.

True or false: Some diseases are actually due to inappropriate expression or over expression of a gene.

true Reason: For example, many cancers occur when an unwanted gene is expressed.

True or false: A genetic element such as a plasmid or a bacteriophage that is used to introduce genetic material into a cloning host during recombinant DNA experiments is called a vector.

true Reason: Plasmids or bacteriophages are good vectors.

True or false: Restriction endonucleases protect a living bacterium from foreign DNA.

true Reason: Bacteria destroy foreign DNA entering their cells by using restriction endonucleases.

True or false: Broad spectrum antibiotics can lead to superinfections.

true Reason: These affect beneficial resident populations which can lead to superinfections.

True or false: There are thousands of different restriction enzymes that each cut DNA at a different sequence.

true Reason: Each type has a known sequence of 4-10 base pairs as its target.

A genetic element such as a plasmid or a virus that is used to introduce genetic material into a cloning host during recombinant DNA experiments is called a(n)

vector

the second step of recombinant DNA technology is to insert the gene of interest into a(n) ---

vector

A large number of prescriptions for drugs are written for infections that are caused by --- pathogens, which antibiotics are unable to target.

viral/resistant

The most common vector used in gene therapy is a ______.

virus