mcgraw hill microbiology test bank

Correct Answer: B

Rationale: The correct answer is B because the nucleocapsid of viruses is composed of the genome (genetic material) and the capsid (protein coat). The genome contains the viral genetic information, while the capsid protects the genome and helps in viral attachment and entry into host cells. Choice A is incorrect because the envelope is not part of the nucleocapsid but surrounds the capsid in some viruses. Choice C is incorrect as spikes are surface proteins on the viral envelope, not part of the nucleocapsid. Choice D is also incorrect because the envelope is external to the capsid and genome in many viruses.

Correct Answer: D

Rationale: The correct answer is D: components of the gram-negative cell wall. Bacterial endotoxins are lipopolysaccharides found in the outer membrane of gram-negative bacteria. They are released upon bacterial cell lysis and can cause severe immune responses. A: Proteins in the cell wall - This is incorrect because endotoxins are not proteins but rather lipopolysaccharides. B: Secreted into the environment - Endotoxins are not actively secreted but are released upon cell death or lysis. C: Components of the gram-positive cell wall - Gram-positive bacteria do not have an outer membrane with lipopolysaccharides, so endotoxins are not found in the gram-positive cell wall.

Correct Answer: B

Rationale: The correct answer is B because the term "infectious process" refers to all biological processes that occur after the attachment and penetration of microbes into the host organism, regardless of whether there are clinical manifestations. This includes the colonization, multiplication, and spread of the microorganisms within the host. Explanation: A: Incorrect because it only mentions the attachment and penetration of microbes into the microorganism, missing the subsequent processes. C: Incorrect because it is too specific, stating that the penetration of microbes always manifests clinically, which is not always the case. D: Incorrect because there is a correct answer, which is B, as explained above.

Correct Answer: A

Rationale: Step 1: Gram-negative bacillus indicates P. aeruginosa, known for causing wound infections. Step 2: Semi-transparent mucous colonies of blue-green color with a pearlescent appearance are characteristic of P. aeruginosa. Step 3: Specific odor of violets or jasmine is a unique feature of P. aeruginosa. Therefore, the correct answer is A: P. aeruginosa. Summary: - B: P. vulgaris typically forms yellow colonies and doesn't have the characteristic odor. - C: S. aureus forms creamy white colonies, not blue-green, and has a distinct odor. - D: S. pyogenes forms grayish-white colonies and doesn't have the unique characteristics described.

Correct Answer: C

Rationale: The correct answer is C: Plague. Yersinia pestis is a bacterium that causes plague, a serious infectious disease transmitted through infected fleas or direct contact with infected animals. Yersinia pestis does not cause Cholera (choice A) or AIDS (choice B). Choice D, None of the above, is incorrect as Yersinia pestis is indeed the causative agent of plague.