BIOL TEST 4 Flashcards

The enzyme___ adds nucleotides of DNA in the ___direction when DNA is being semi-conservatively replicated.

1. DNA polymerase III; 3’ → 5’
2. DNA polymerase I; 3’ → 5’
3. DNA polymerase III; 5’ → 3’
4. DNA polymerase I; 5’ → 3’

Which of the following regions of DNA would be of most value for forensic analysis?

1. DNA sequences that differ among humans, with a maximum of two different alleles
2. DNA sequences that are quite variable with multiple different alleles
3. DNA sequences that are typically identical for all humans
4. Most DNA sequences are equally valuable for forensic analysis.

The separated segments of DNA produced by restriction endonucleases are

1. restriction fragments.
2. plasmids.
3. restriction enzymes.
4. vectors.

The following steps are presented in the correct order for polymerase chain reaction.

1. denaturation, extension, priming
2. extension, denaturation, priming
3. denaturation, priming, extension
4. priming, extension, denaturation

______ is the enzyme responsible for unwinding the DNA double helix.

1. Reverse transcriptase
2. Helicase
3. Ligase
4. Polymerase

Gene probes can be labeled for detection with

1. radioisotopes.
2. fluorescent dyes.
3. enzymes.
4. All of these choices are correct.

Which of the following is less subject to degradation than is chromosomal DNA and is used as an evolutionary time clock?

1. mRNA
2. chloroplast DNA
3. tRNA
4. rRNA
5. mitochondrial DNA

The various techniques by which scientists manipulate DNA in the lab are called

1. gel electrophoresis.
2. genetic engineering.
3. recombinant DNA.
4. biotechnology.

Which step involves transformation?

1. Target DNA is removed from cells and isolated.
2. The desired protein is produced by the cloning host.
3. Target DNA and plasmid are treated with the same restriction endonuclease.
4. The gene is amplified by multiplication of the cloning host.
5. The cloning host takes up a plasmid.

Which of the following is often used in forensic science to distinguish one sequence of DNA from another by comparing the sequence of the strands at specific loci?

1. gene therapy
2. DNA fingerprinting
3. cloning
4. antisense therapeutic

The human gene for a protein hormone has been isolated. Scientists want to introduce this gene into a bacterial host, modifying the bacteria so that it can be used to produce this hormone. After successfully introducing the gene on a plasmid, the bacteria produced the protein hormone, but the protein was defective, longer than normal, with intervening stretches of amino acids not found in the native protein. Which solution would be most likely to resolve this problem?

1. Introduce human ribosomes into the bacteria.
2. Start over, introducing a complementary DNA (cDNA) copy of the gene into the bacterial host.
3. Treat the defective protein with enzymes.
4. Introduce human mRNAs into the bacterial host.

The fluorescent in situ hybridization (FISH) probes are applied to intact cells and observed microscopically for the presence and location of

1. proteins.
2. recombinant DNA.
3. RNA.
4. specific genetic marker sequence on genes.
5. DNA.

The Southern blot technique enables detection of specific sequences

1. of sugars in polysaccharides.
2. in RNA.
3. of amino acids in proteins.
4. in DNA.

Amplification of DNA is accomplished by

1. DNA sequencing.
2. Southern blot.
3. All of these choices are correct.
4. gene probes.
5. polymerase chain reaction.

The common material(s) used in microarrays are

1. silicon.
2. nylon.
3. All of these choices are correct.
4. glass.

Newer vectors that can hold 45 kb are called

1. yeast artificial chromosomes.
2. hosts.
3. bacterial artificial chromosomes.
4. cosmids.

All of the following are characteristics that make plasmids good cloning vectors, except

1. they can carry genetic markers, such as antibiotic resistance genes.
2. they can accept a relatively large amount of foreign DNA.
3. they are small.
4. they are well characterized.
5. they can be transferred into appropriate host cells

DNA polymerases used in PCR

1. include Taq polymerases and Vent polymerase.
2. must remain active at very cold temperatures.
3. All of these choices are correct.
4. are labeled with fluorescent dyes.
5. use an RNA template to make complementary DNA.

Transgenic animals

1. commonly include mice.
2. will pass the genes on to their offspring.
3. All of these choices are correct.
4. are often obtained from germ line engineering.
5. can be engineered to become factories for manufacturing proteins.

The commercial product Frostban contains a genetically engineered strain of

1. Pseudomonas syringae.
2. Thermus aquaticus.
3. Saccharomyces cerevisiae.
4. Escherichia coli.
5. Pseudomonas fluorescens.

The use of a physical or chemical process to destroy vegetative pathogens on inanimate objects is called

1. degermation.
2. sanitization.
3. disinfection.
4. sterilization.
5. antisepsis.

All of the following are major categories of microbial control methods except

1. chemical agents.
2. genetic methods.
3. physical agents.
4. mechanical removal methods.

Endospores can be killed by

1. dry heat at 170°C for 2 hours.
2. ethylene oxide for 3 or more hours.
3. glutaraldehyde for 8 or more hours.
4. All of the choices are correct.
5. incineration.

Which common hospital pathogen is able to grow abundantly in soap dishes?

1. Escherichia coli
2. Hemophilus influenzae
3. Pseudomonas
4. Mycobacteria tuberculosis
5. Salmonella

Alcohols

1. are skin degerming agents.
2. denature proteins when in a 50–95% solution.
3. are used to disinfect items by soaking.
4. All of the choices are correct.
5. at 50% or higher concentrations dissolve cell membrane lipids.

All of the following are true of food irradiation except

1. it can kill bacterial pathogens on the food.
2. it can inhibit the sprouting of white potatoes.
3. it can reduce the number of food-borne deaths each year.
4. it can kill insects on the food.
5. it makes the food less nutritious.

Moist heat is more efficient at killing microbes and is effective at lower temperatures or shorter exposure times than dry heat.

1. True
2. False

Microbiological contaminants are best described as

1. vegetative microbes present on or in a substance.
2. pathogenic microbes present on or in a substance.
3. unwanted microbes present on or in a substance.
4. any and all microbes present on or in a substance.

The use of chemical agents directly on exposed body surfaces to destroy or inhibit vegetative pathogens is

1. degermation.
2. sterilization.
3. disinfection.
4. antisepsis.
5. sanitization.

Which of the following does not contain a heavy metal?

1. Merthiolate
2. Zinc
3. Tincture of iodine
4. Mercurochrome
5. Silver nitrate solutions

Physical agents for controlling microbial growth include all of the following except

1. hydrogen peroxide.
2. pasteurization.
3. ultraviolet radiation.
4. boiling water.
5. HEPA filters.

Isopropyl alcohol wiped across a skin site can sterilize it

1. True
2. False

All of the following are correct about iodophors, except

1. a common iodophor is Betadine.
2. it is less prone to staining or irritating tissue.
3. this formulation increases its penetration.
4. they are complexes of iodine and a neutral polymer.
5. this formulation allows a quick release of free iodine.

You are a scientist isolating a particular microbe from a water sample. As a first step, you need to inoculate a broth culture with your microbe using a sterile loop. Which of the following is the most appropriate way to sterilize your loop before inoculation? Consider effectiveness, time, and safety.

1. Sterilize the loop by exposure to gamma radiation.
2. Sterilize the loop by using a bunsen burner at your bench.
3. Sterilize loop by exposure in an ethylene oxide chamber for 1-2 hours.
4. Wash the loop with soapy water.

Ethylene oxide is

1. used as an antiseptic against anaerobes.
2. sporicidal.
3. only effective with high heat.
4. a halogen.
5. the active agent in household bleach.

Disinfection of beverages, such as apple juice, milk, and wine, is optimally achieved by

1. filtration.
2. boiling water.
3. pasteurization.
4. moist heat autoclave.
5. chlorination.

The chemical agent(s) that produces highly reactive hydroxyl-free radicals and also decomposes to O₂ gas is/are

1. chlorhexidine.
2. iodophors.
3. Cidex.
4. cationic detergents.
5. hydrogen peroxide.

Scrubbing or immersing the skin in chemicals to reduce the numbers of microbes on the skin is called

1. sterilization.
2. degermation.
3. disinfection.
4. sanitization.

Which of the following sequences of DNA would most likely be damaged by UV radiation?

1. AGAGCGCAT
2. ATAGAGCGC
3. AGTACGCAT
4. AGTTCGCTT

Commercial products containing which types of chemicals are more effective at killing microorganisms?

1. Carbohydrate
2. Bacteriostatic
3. Lead
4. Bacteriocidal

Antibiotics are derived from all the following except

1. Cephalosporium.
2. Streptomyces.
3. Staphylococcus.
4. Bacillus.
5. Penicillium.

Ciprofloxacin is used to treat viral respiratory infections.

1. True
2. False

Which of the following is/are true of antibiotic usage and the development of antibiotic resistance?

1. Antibiotics cause mutations (antibiotics are mutagens), thus resulting in increasingly resistant bacterial populations.
2. Antibiotics increase the rate of bacterial transformation, conjugation, and transduction, and thus increase the spread of antibiotic resistance.
3. All of these choices are correct.
4. Antibiotics cause R-plasmids to form and cause their transfer, spreading antibiotic resistance.
5. Antibiotics select for resistant mutants and bacteria possessing R-plasmids, increasing their frequency in the population.

An antimicrobic with a low therapeutic index is a safer choice compared to a drug with a high therapeutic index.

1. True
2. False

Which of the following is not a mode of action of an antiviral?

1. Inhibit DNA synthesis
2. Bond to ergosterol in the cell membrane
3. Block maturation
4. Block transcription and translation
5. Block viral entry into a host cell

There are fewer antifungal, antiprotozoan, and antihelminth drugs compared to antibacterial drugs because these organisms

1. are so similar to human cells that selective drug toxicity is difficult to achieve.
2. are parasites found inside human cells.
3. are not affected by antimicrobics.
4. do not cause many human infections.
5. have fewer target sites compared to bacteria.

Which is the best guide for selecting an effective antibiotic?

1. Location of the patient’s infection
2. Identification of the microbe causing the infection
3. History of prior antibiotics prescribed for the patient
4. Results of antimicrobial susceptibility testing

One of the greatest challenges in development of antivirals is finding drugs that are

1. not likely to disrupt the normal microbiota of the patient.
2. selectively toxic for viruses.
3. absorbed by the GI tract.
4. administered orally.

A chemical that inhibits beta-lactamase enzymes is

1. clavulanic acid.
2. aztreonam.
3. synercid.
4. imipenem.
5. penicillinase.

The cellular basis for bacterial resistance to antimicrobics include

1. prevention of drug entry into the cell.
2. alteration of drug receptors on cell targets.
3. synthesis of enzymes that alter drug structure.
4. All of these choices are correct.
5. bacterial chromosomal mutations.

Which of the following is true of the analysis of DNA fragments using gel electrophoresis?

1. DNA fragments are stained to visualize them.
2. DNA has an overall negative charge and moves to the positive pole.
3. An electric current through the gel causes DNA fragments to migrate.
4. Larger DNA fragments move slowly and remain closer to the wells.
5. All of these choices are correct.

All of the following are correct about DNA fingerprinting, except

1. it displays the unique pattern of an individual's DNA fragments.
2. it can be used on hair and saliva.
3. it cannot be used on specimens older than five years.
4. it can be used to analyze evidence when only minute amounts of DNA are found.
5. it is routine to use it as trial evidence in the U.S.

In order to ensure compatibility between the target DNA and the plasmid DNA,

1. desired protein is produced by cloning host.
2. gene is amplified by multiplication of cloning host.
3. target DNA is removed from cells and isolated.
4. cloning host is treated with calcium chloride and receives plasmid.
5. target DNA and plasmid are treated with the same restriction endonuclease.

_________ is replacement therapy that benefits patients with emphysema.

1. Macrophage
2. Interferon
3. Lipase
4. Antitrypsin

When a control agent targets the metabolic processes of microbial cells, active younger cells typically die more rapidly than older cells.

1. True
2. False

Using toilet bowl cleaner and nonionizing radiation on inanimate surfaces only removes or kills vegetative bacteria. The term that best describes this action is

1. sterilization.
2. disinfection.
3. antisepsis.
4. degermation.

Bacteriostatic agents kill bacterial cells.

1. True
2. False

The thermal death time for E. coli at 63°C was determined to be 20 minutes. Predict the effect on thermal death time if the temperature is increased to 67°C.

1. The thermal death time will be shorter.
2. There is not enough information to make this prediction.
3. There will be no change in thermal death time.
4. The thermal death time will be longer.

Which molecule is composed of long chains of nucleic acids?

1. Protein
2. Carbohydrate
3. Lipid
4. DNA

Decontamination with a particular agent requires the same amount of time regardless of the number of microbial contaminants.

1. True
2. False

A recirculating fountain is contaminated with Cryptosporidium, whose spores are resistant to chlorination and small enough to pass through swimming pool filters. What is the best water treatment option?

1. Increase the concentration of chlorine in the water
2. Only use autoclaved water
3. Integrate ultraviolet light into the filtration system
4. Switch from chlorine treatment to treatment with gluteraldehyde

This % of infections involves biofilms, complex communities of microorganisms growing within an extracellular matrix.

1. 50
2. 60
3. 40
4. 70

Name the drugs that are similar to penicillins but with greater resistance to beta-lactam rings.

1. Streptomycins
2. Carbapenems
3. Macrolides
4. Tetracyclines

The drug used against intestinal anaerobic bacteria, that can also alter normal microbiota causing antibiotic-associated colitis is

1. ciprofloxacin.
2. bacitracin.
3. gentamicin.
4. chloramphenicol.
5. clindamycin.

Which is mismatched?

1. Fleming–penicillin
2. Ehrlich–tetracycline
3. Domagk–sulfonamide
4. Florey and Chain–penicillin

Staphylococcus infections can be treated with penicillins.

1. True
2. False

Taking multiple drugs at the same time to fight an infection is called

1. combined therapy.
2. narrow-spectrum.
3. broad-spectrum.
4. prophylaxis.

Which type of DNA analysis is likely to be most effective when analyzing the ancient remains of a mummified body?

1. analysis of short tandem repeats
2. analysis of cDNA
3. whole genome sequencing
4. analysis of mitochondrial DNA

Which of the following chemicals is a disinfectant for soft contact lenses?

1. Hypochorites
2. Hydrogen peroxide
3. Glutaraldehyde
4. Alcohol
5. Hexachlorophene

Electrons are ejected from atoms in cells when organisms are exposed to

1. ethyl alcohol.
2. gamma rays and X-rays.
3. hydrogen peroxide.
4. dessication.
5. ultraviolet light.

Aniline dyes like crystal violet have antimicrobial activity particularly against gram-positive bacteria and some fungi.

1. True
2. False

Drug susceptibility testing

1. determines the pathogen’s identity.
2. determines the pathogen’s response to various antimicrobics.
3. determines the patient’s response to various antimicrobics.
4. determines if normal flora will be affected by antimicrobics.
5. determines if the drug is increasing to toxic levels in a patient.

Antimicrobics that are macrolides

1. are very narrow-spectrum drugs.
2. include azithromycin, clarithromcyin, and erythromycin.
3. include tetracyclines.
4. are hepatotoxic.
5. disrupt cell membrane function.

Antimicrobics effective against a wide variety of microbial types are termed

1. synthetic drugs.
2. broad-spectrum drugs.
3. narrow-spectrum drugs.
4. semisynthetic drugs.
5. antibiotics.

All of the following are correct about allergic reactions to drugs except

1. anaphylaxis can occur.
2. hives may be the result after the drug is taken.
3. the drug acts as an antigen.
4. the greatest number of antimicrobic allergies are to the penicillins.
5. allergic reactions generally will occur the first time a person takes the drug.