Microbiology An Introduction 13th Edition Test Bank

Correct Answer: A

Rationale: The correct answer is A: Chingamin. Chingamin is a type of antimalarial drug that is commonly used for individual prevention of malaria. It works by targeting the malaria parasite in the body, preventing its growth and spread. Rifampicin (B), Ampicillin (C), and Gentamicin (D) are not effective for preventing malaria as they are antibiotics that target bacterial infections, not parasitic infections like malaria. Therefore, Chingamin is the most appropriate choice for individual prevention of malaria due to its specific antimalarial properties.

Correct Answer: C

Rationale: The correct answer is C because the main factor in the pathogenicity of diphtheria is the exotoxin produced by the bacterium Corynebacterium diphtheriae. This exotoxin inhibits protein synthesis in host cells, leading to tissue damage and the characteristic symptoms of diphtheria. A: The metachromatic bodies of Ernst-Babes are not the main factor in diphtheria pathogenicity. B: While endotoxins can contribute to the pathogenicity of some bacteria, in diphtheria, the main factor is the exotoxin. D: This is incorrect as the main factor in diphtheria pathogenicity is the exotoxin.

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: C

Rationale: The correct answer is C: mesophiles. Mesophiles are microorganisms that thrive in moderate temperatures, typically between 25�C and 40�C. This temperature range is ideal for their growth and reproduction. Thermophiles (A) prefer high temperatures, psychrophiles (B) thrive in cold temperatures, and psychrotrophs (D) can grow at refrigeration temperatures but have an optimal range above 20�C. Therefore, the mesophiles are the best fit for organisms that show optimal growth in moderate temperatures.

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.