microbiology an introduction 13th edition test bank

Correct Answer: A

Rationale: The correct answer is A: Neisseria gonorrhoeae. This bacterium is the likely causative agent of the patient's symptoms based on the presentation of dysuria and purulent discharge, which are classic signs of gonorrhea. Gram-negative diplococci are characteristic of Neisseria species. Neisseria gonorrhoeae is a sexually transmitted pathogen commonly associated with urethral infections. Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis are not typically associated with urethral discharge and are not Gram-negative diplococci.

Correct Answer: A

Rationale: The correct answer is A: proteins. Enzymes are mostly composed of proteins due to their complex structure and specific amino acid sequences that are essential for their catalytic activity. Proteins have active sites that bind to substrates and facilitate chemical reactions. Lipids (B), nucleic acids (C), and carbohydrates (D) do not possess the necessary properties and structures to function as enzymes. Lipids serve as energy storage molecules and cell membrane components, nucleic acids store genetic information, and carbohydrates are primarily used for energy production.

Correct Answer: C

Rationale: The bacterial capsule is composed of polysaccharides. This outer layer helps bacteria evade the host immune system, protect against desiccation, and aid in attachment to host cells. Polysaccharides are long chains of sugar molecules, providing a protective barrier for the bacteria. Lipopolysaccharides (choice A) are found in the outer membrane of Gram-negative bacteria and are not a major component of the capsule. Teichoic acid (choice B) is a component of the cell wall in Gram-positive bacteria, not the capsule. Peptidoglycan (choice D) is another component of the cell wall but is not part of the capsule.

Correct Answer: B

Rationale: The correct answer is B because intensity, frequency, and thickness of the sample are key factors that determine the effects of different kinds of radiation. Intensity refers to the amount of energy carried by the radiation, frequency indicates the number of waves per unit time, and the thickness of the sample affects the penetration of radiation. These factors directly influence the interactions of radiation with matter, such as ionization and heating effects. A is incorrect because wavelength is not a major factor in determining the effects of radiation. C is incorrect because distance and nature of the sample are not as significant as intensity, frequency, and thickness. D is incorrect because chemical composition and shielding, while important in certain contexts, are not the primary factors affecting the effects of radiation.

Correct Answer: D

Rationale: The correct answer is D, All of these. Orthopoxvirus genus includes Vaccinia, Smallpox, and Cowpox viruses. They share similar characteristics such as brick-shaped virions and double-stranded DNA genomes. Vaccinia virus is used in smallpox vaccine, Smallpox virus caused the eradicated disease, and Cowpox virus can infect both animals and humans. Therefore, all three viruses belong to the Orthopoxvirus genus. Choices A, B, and C are incorrect because they each represent a different virus from the genus Orthopoxvirus.