microbiology an introduction 12th edition test bank

Correct Answer: A

Rationale: The correct answer is A: viral DNA polymerase. Herpesviruses require viral DNA polymerase for viral DNA replication. This enzyme is responsible for synthesizing new DNA strands using existing viral DNA as a template. Ribonucleotide reductase (B) is not directly involved in DNA replication but in the synthesis of deoxyribonucleotides. Neuraminidase (C) is an enzyme found in influenza viruses, not herpesviruses. Thymidine kinase (D) is involved in nucleotide metabolism but is not essential for viral DNA replication in herpesviruses.

Correct Answer: A

Rationale: The correct answer is A because immunity in syphilis is nonsterile, meaning that individuals who have been infected may still carry the bacteria and be capable of transmitting the disease. This is due to the ability of the bacterium causing syphilis, Treponema pallidum, to evade the immune system by hiding within host cells. Option B, antitoxic, is incorrect because syphilis is not caused by a toxin produced by the bacteria, but rather by the bacterium itself. Option C, humoral, is also incorrect as syphilis immunity involves both humoral (antibody-mediated) and cell-mediated immune responses, not solely humoral immunity. Option D is incorrect as it includes all three options, whereas in reality, the immunity in syphilis is primarily nonsterile.

Correct Answer: B

Rationale: Facultative anaerobes can switch between aerobic and anaerobic metabolism based on oxygen availability. This flexibility enables them to grow in both oxygen-rich and oxygen-poor environments, making choice B correct. Choice A is incorrect because facultative anaerobes do not require oxygen for survival. Choice C is incorrect as obligate anaerobes cannot grow in the presence of oxygen. Choice D is incorrect because obligate anaerobes cannot tolerate any amount of oxygen.

Correct Answer: A

Rationale: The correct answer is A: McConkey agar. Selective media selectively inhibit the growth of certain organisms while allowing others to grow. McConkey agar contains crystal violet and bile salts that inhibit the growth of Gram-positive bacteria, making it selective for Gram-negative bacteria. Choices B and C are not selective media, as they do not specifically inhibit the growth of certain types of bacteria. Choice D is incorrect as McConkey agar is indeed an example of selective media.

Correct Answer: B

Rationale: The correct answer is B: intravenous administration. This route bypasses the first-pass metabolism, allowing the drug to directly enter the bloodstream for immediate distribution. In contrast, on the skin (A) and sublingual (D) routes have slower absorption rates due to barriers like skin layers or mucous membranes. Intramuscular (C) absorption is slower than intravenous due to slower perfusion rates in muscle tissues. Overall, intravenous administration provides the fastest and most direct route for drug absorption, making it the most rapid method.