MCB Exam 3 Practice

Which type of virus is most likely to be released by lysis of the host cell? Enveloped virus Non-enveloped virus

T/F: Bacterial viruses are so named because they have prokaryotic cell structures similar to their bacterial hosts.

Which of the following is not a strategy that bacteria use to resist the action of antibiotics? Modification of the antibiotic by the acetylation or phosphorylation. Cleavage of a key structural component of the antibiotic. Altering cell membrane structure to prevent antibiotic influx. All of the choices are correct.

Many species in the phylum Crenarchaeota are considered extreme thermophiles or _______, which can grow at temperatures above 100°C.

When a chemotherapeutic agent is effective against many different pathogens, it is said to be a __________ antibiotic.

Which of the following diseases is (are) caused by prions? Scrapie Mad cow disease Kuru and Creutzfeldt-Jakob Disease All of the choices are correct.

Prions are of significance because they cause infections of

The presence or absence of an envelope is not useful in classifying viruses because any given virus may at one time have an envelope and at another time not have an envelope.

An acronym that describes sequences of a protein-coding gene that specify the amino acid sequence is ________.

Viruses infecting protists, including algae, have never been detected.

The _____ is the collection of microorganisms (and their genes) that are normally present in and on an organism.

Isoniazid is a narrow-spectrum antibiotic that is not useful as a chemotherapeutic agent. is one of the few drugs effective against Mycobacterium tuberculosis. is one of the few drugs effective against systemic fungal infections. None of the choices are correct.

The genome sequence of Treponema pallidum almost immediately provided explanations for how this organism causes syphilis. should ultimately help us understand the mechanism by which this organism causes syphilis. identified proteins that have already been used to produce the first successful vaccine for syphilis. has led us to be able to completely eradicate this organism.

Whose discovery of streptomycin stimulated an intense search for other antibiotics? Waksman Ehrlich Fleming Pasteur

For a temperate phage to produce more phage, which of the following must happen? Lysogeny Induction Lysogenic conversion Prophage formation

Restriction endonucleases are produced by fungi. bacteria. protozoa. plants. All of the choices are correct.

Bacteria in biofilms or abscesses may be replicating very slowly and are therefore resistant to chemotherapy because many agents affect pathogens only if they are actively growing and dividing.

Chemotherapeutic agents that are artificially produced are most specifically referred to as __________. antimicrobial agents synthetic drugs antibiotics semisynthetic drugs

Penicillin G is frequently injected but not normally given orally because it is rapidly degraded in the stomach.

Enveloped viruses may enter their host cells by engulfment within coated vesicles (endocytosis).

Metagenomics has helped us to understand that the composition of the microbiome may be connected to many aspects of human health.

Which of the following is likely to have the most toxic side effects to humans? Inhibitors of cell wall synthesis Inhibitors of protein synthesis Disrupters of cell membrane structure Inhibitors of DNA synthesis

When a eukaryotic gene is cloned into a bacterium, the advantage of a complementary DNA (cDNA) gene being used instead of fragments of genomic DNA is that the promoter and terminator are found in the cDNA gene but not in the genomic fragment. the introns have been removed from the cDNA gene but not from the genomic fragment. the cDNA is made with the nucleotides found in the prokaryote but not in the eukaryote. There is no advantage to using a cDNA gene rather than a genomic fragment.

Which cloning vector should be used to express a 500-kb DNA fragment in Saccharomyces cerevisiae? Multiple Choice YAC BAC pUC19 ?1059

Isoelectric focusing separates proteins based on the pH at which they are electrically neutral. separates proteins based on their size and shape. directly reveals the identity of unknown proteins in a complex mixture. focuses the data gathered onto a specific protein or ORF.

Ampicillin, like penicillin, must be administered by injection because it is rapidly degraded in the stomach and cannot, therefore, be given orally.

The mechanism of pathogenesis by prions may involve a conformational change in the prion protein (PrP) to an abnormal form.

A(n) __________ is a drug that blocks the function of a metabolic pathway.

Poliovirus receptors are found Multiple Choice in cells of all tissues. in spinal cord anterior horn cells only. in nasopharynx, gut, and spinal cord anterior horn cells. in gut cells only.

A(n) __________ is a latent form of a virus genome that remains within the host without destroying it.

The antiviral drugs currently approved for use in HIV disease include nucleoside reverse transcriptase inhibitors. nonnucleoside reverse transcriptase inhibitors. protease inhibitors. fusion inhibitors. All of the choices are correct.

A __________ is a DNA molecule used in hybridization reactions to detect the presence of a particular gene in separated DNA fragments. plasmid vector probe blot

Who is usually credited with the discovery of penicillin? Fleming Florey and Chain Duchesne Ehrlich

Who is generally credited with the discovery of sulfanilamide as a chemotherapeutic agent? Gerhard Domagk Ernest Duchesne Ernst Chain Robert Koch

A PCR procedure that allows a determination of the amount of a particular DNA fragment that is present in a sample is called Multiple Choice quantitative PCR. analytical PCR. real-time PCR. reverse PCR.

Defining features of the halobacteria include absolute dependence on temperatures above 65ºC for growth. the production of methane. absolute dependence on a high concentration of NaCl for growth. absolute dependence on low pH conditions for growth.

The combination of all the genes present in the human genome and those present in the trillions of microbes living in and on adults is known as the human __________.

Electroporation is commonly used to introduce recombinant DNA molecules into cells.

Which of the following best describes the basis for separation of DNA fragments during agarose gel electrophoresis? The fragments with the highest percentage of G and C will migrate fastest. The fragments with the highest percentage of A and T will migrate fastest. The largest fragments will migrate fastest. The smallest fragments will migrate fastest.

In a disk diffusion assay for drug susceptibility, a drug producing a larger clear zone is always more effective than a drug than to one producing a smaller clear zone.

Promoters for genes that code for proteins can be isolated from a cDNA library.

Most enveloped viruses use the host __________ membrane as their envelope source. plasma nuclear mitochondrial none of these

Environmental genomics is sometimes called metagenomics.

Antibiotics incorporated into the culture medium can select against organisms that have not incorporated the plasmid. select against organisms that have incorporated a plasmid not containing the desired gene. enhance production of recombinant proteins. select against organisms that have not incorporated the plasmid and select against organisms that have incorporated a plasmid not containing the desired gene

Which of the following is/are necessary for the replication of a satellite virus? Host cell only Helper virus only Prion only Host cell and helper virus

Most antiprotozoan drugs have few side effects since there are numerous cellular targets found in protozoa but not found in host cells that can be targeted with antiprotozan drugs.

Analysis of the nucleotide sequence of the genome of microorganisms has revealed important information about their metabolic potential.

The function of the viral protein coat is to protect the viral genetic material. aid in the transfer of the viral genetic material between host cells. elicit the production of protective antibodies. protect the viral genetic material and aid in the transfer of the viral genetic material between host cells.

Isoelectric focusing separates proteins based on the pH at which they are electrically _________.

Aminoglycoside antibiotics inhibit cell wall synthesis. inhibit folic acid biosynthesis. bind to the 30S ribosomal subunit. bind to bacterial DNA polymerase.

A temperate phage always lyses its host cell.

Which of the following inhibits protein synthesis? Dapsone Erythromycin Penicillin Isoniazid

Which of the following is/are not true about viral envelopes? The envelope proteins are virus specific. The envelope lipids and carbohydrates are derived from the host. They are typical lipid monolayers with embedded viral proteins. The envelope proteins are virus specific and the envelope lipids and carbohydrates are derived from the host.

ORF refers to the location of the start site of transcription. the region of a gene that codes for a protein or a functional RNA product. the region of a gene that serves as the promoter. the region between the ribosome binding site and translation initiation codon.

Which of the following encodes its own capsid proteins? Satellite virus Satellite DNA Satellite RNA Prion

When two or more genes from the same genome have nucleotide sequences so alike that they most probably arose from gene duplication those genes are called _______. homologs orthologs paralogs duologs

Which of the following is not true about Kirby-Bauer disk diffusion method? After inoculation of bacteria, the agar surface is dried for about 5 minutes and the appropriate antibiotic test disks are placed on it. The plate is placed at 35°C for 16 to 18 hours of incubation. Bacteria used to swab plate should be at least a week old. The diameters of the zones of inhibition are measured to the nearest millimeter.

Defining features of the halobacteria include Multiple Choice absolute dependence on temperatures above 65ºC for growth. the production of methane. absolute dependence on a high concentration of NaCl for growth. absolute dependence on low pH conditions for growth.

In order for successful antibiotic therapy, the in vivo level of the antibiotic must be greater than or equal to the MIC.

Specialized transduction can be carried out by Multiple Choice any bacteriophage. any temperate bacteriophage. only those temperate bacteriophages that integrate into the host chromosome. Correct All of the choices are correct.

The production of cholera toxin by virulent strains of Vibrio cholera is dependent upon genes in a bacteriophage. This is an example of Multiple Choice lysogenic conversion. induction. bacterial transformation. transduction.

A drug that disrupts a microbial function not found in animal cells usually has a higher therapeutic index.

The method of nucleotide sequence determination that utilizes dideoxynucleotides was developed by _________.