Biology Competitive Exam 2021-2022
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Questions and Answers

Which drug inhibits DNA gyrase?

  • Chloramphenicol
  • Penicillin
  • Trimethoprim
  • Ciprofloxacin (correct)
  • Which antimicrobial drug is synthetic?

  • Penicillin
  • Actinomycin
  • Neomycin
  • Sulfanilamide (correct)
  • Which clinical situation is best treated with a narrow-spectrum antimicrobial drug?

  • Treatment of a polymicrobic mixed infection in the intestine
  • Empiric therapy of pneumonia while waiting for culture results
  • Treatment of strep throat caused by culture identified Streptococcus pyogenes (correct)
  • Prophylaxis against infection after a surgical procedure
  • Which of the following is not a type of β-lactam antimicrobial?

    <p>Glycopeptides</p> Signup and view all the answers

    Which resistance mechanism describes the function of β-lactamase?

    <p>Drug inactivation</p> Signup and view all the answers

    Which of the following is present in prokaryotes but not eukaryotes?

    <p>simultaneous transcription and translation</p> Signup and view all the answers

    The nitrogen bases in DNA are bonded to the:

    <p>deoxyribose</p> Signup and view all the answers

    Which statement about IgE is true?

    <p>IgE is involved in Type I hypersensitivity reactions.</p> Signup and view all the answers

    Which cells are responsible for killing their targets via perforin and granzyme B?

    <p>Cytotoxic T cells</p> Signup and view all the answers

    A primary role for antibodies in resistance to bacterial infection is:

    <p>activation of the alternative complement pathway</p> Signup and view all the answers

    Which process involves the uptake of naked DNA from the environment by a bacterial cell?

    <p>Transformation</p> Signup and view all the answers

    Which type of microorganism uses CO2 as a carbon source and inorganic chemical compounds as an energy and electron source?

    <p>Chemolithoautotroph</p> Signup and view all the answers

    Which compound lacks the presence of phosphates in the structure of a Gram-positive bacterial cell wall?

    <p>Tichuronic acid</p> Signup and view all the answers

    Which microorganism type cannot synthesize a growth factor?

    <p>Auxoheterotrophic</p> Signup and view all the answers

    At what agar concentration does the movement of Proteus bacteria inhibit?

    <p>5%</p> Signup and view all the answers

    Which type of microorganism is Nitrosomonas?

    <p>Chemolithoautotroph</p> Signup and view all the answers

    Which one of the following is most responsible for the nature of the lesion on the foot caused by Staphylococcus aureus?

    <p>Superantigen toxin (StaphSAg)</p> Signup and view all the answers

    What is the best explanation for a negative blood culture in the case of Staphylococcal TSS?

    <p>This is typical in staphylococcal TSS. Only the StaphSAg needs to circulate</p> Signup and view all the answers

    Which type of enzyme inhibitor affects the enzyme activity by binding to the enzyme at a site other than the active site?

    <p>Non-competitive inhibitor</p> Signup and view all the answers

    Which method is the best for determining the etiology of a sore throat?

    <p>Throat culture</p> Signup and view all the answers

    What does virulence refer to?

    <p>A term which presumes pathogenicity, but allows expression of degrees from low to extremely high.</p> Signup and view all the answers

    Which laboratory test is most likely to confirm the diagnosis of Lyme disease?

    <p>Borrelia burgdorferi immunoassay plus immunoblot</p> Signup and view all the answers

    An F-pilus is essential for:

    <p>Plasmid transfer by conjugation</p> Signup and view all the answers

    Which of the following statements about gene expression is false?

    <p>Translation begins at a site called a promoter.</p> Signup and view all the answers

    Which of the following is NOT characteristic of eukaryotic gene expression?

    <p>The mRNA is often polycistronic</p> Signup and view all the answers

    What is a distinguishing feature of eukaryotic mRNA?

    <p>The presence of a 5' cap.</p> Signup and view all the answers

    Which process is not typically associated with bacterial conjugation?

    <p>Generalized transduction</p> Signup and view all the answers

    Study Notes

    Competitive Exams for the Academic Year 2021-2022

    Question 1

    • Chemoautotrophic microorganisms can use CO2 as a source of carbon and inorganic chemicals as a source of energy and electrons.
    • Teichoic acid is a component that lacks phosphate in the cell wall of Gram-positive bacteria.
    • Lipoteichoic acid is a component that lacks phosphate in the cell wall of Gram-positive bacteria.

    Question 2

    • Types of inhibitors that affect enzyme activity: uncompetitive, competitive, and noncompetitive inhibitors.

    Question 3

    • Nitrosomonas is a chemoautotrophic microorganism.
    • The most responsible factor for the nature of the ulcers on the foot caused by Staphylococcus aureus is Exfoliatin.
    • If the blood culture is negative, the best explanation is that there might be a problem with blood collection.

    The Etiology of Sore Throat

    • The best way to determine the etiology of a sore throat is through a throat culture.

    Virulence

    • Virulence is the ability of bacteria to cause disease when presented with favorable circumstances.

    Lyme Disease

    • The laboratory test that would confirm the diagnosis of Lyme disease is the Borrelia burgdorferi immunoassay.

    Spore Formation

    • The stages of spore formation: sporulation, engulfment, fore-spore formation, and spore maturation.

    F-pilus

    • An F-pilus is essential for plasmid transfer by conjugation.

    Gene Expression

    • False statement: Translation begins at a site called a promoter.
    • True statements: More than one RNA polymerase can be transcribing a specific gene at a given time, More than one ribosome can be translating a specific transcript at a given time, Transcription stops at a site called a terminator, Some amino acids are coded for by more than one codon.

    Eukaryotic Gene Expression

    • False statement: The mRNA is often polycistronic.

    Multiple Choice

    • The nitrogen bases in DNA are bonded to the deoxyribose.
    • Spliceosomes are present in eukaryotes but not prokaryotes, and simultaneous transcription and translation occur in prokaryotes but not eukaryotes.

    Short Answer

    • Conjugation: direct cell-to-cell contact, donor: F+ plasmid, recipient: F- plasmid. Transformation: uptake of free DNA, donor: any DNA source, recipient: competent cells. Transduction: virus-mediated DNA transfer, donor: bacteriophage, recipient: bacterial cells.
    • Selective mediums for Salmonella: LJ medium, XLD agar, and SS agar.
    • True or False: IgE is involved in Type I hypersensitivity reaction, Immune responses are controlled by exclusion of cells from the site of inflammation, Cytotoxic T cells kill targets via perforin and granzyme B, Antibodies activate the alternative complement pathway, Pattern recognition molecules distinguish self from pathogen.

    Additional Questions

    • Microbial activity level can be determined by measuring CO2 production, O2 consumption, or ATP production.
    • Carbon cycle in land: photosynthesis, respiration, decomposition. Carbon cycle in microorganisms: photosynthesis, respiration, fermentation.
    • No significant difference between the water cycle in land and the water cycle on the mainland because the water cycle is a continuous process.

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    This quiz assesses knowledge of biology concepts, including cellular processes and structures. It consists of multiple-choice questions, each worth 20 points.

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