foundations in microbiology test bank

Correct Answer: A

Rationale: Osmosis is the correct answer because it is the process by which water molecules move across a semi-permeable membrane from an area of low solute concentration to an area of high solute concentration. This movement occurs passively, driven by the concentration gradient. Facilitated diffusion (B) involves the transport of specific molecules with the help of carrier proteins, not water. Phagocytosis (C) is a process where cells engulf solid particles, not water molecules. Exocytosis (D) is the process of releasing substances from a cell by fusion of vesicles with the cell membrane, not the transport of water across the membrane.

Correct Answer: C

Rationale: The correct answer is C: IFA - Immunofluorescence assay. Toxoplasmosis and chronic gonorrhea can be detected using serological tests like IFA. IFA detects specific antibodies in the patient's serum by using fluorescently labeled antibodies. This method is highly sensitive and specific for detecting both acute and latent infections. Explanation of Incorrect Choices: A: RIHA - Reverse indirect hemagglutination assay - This test is not commonly used for detecting toxoplasmosis or chronic gonorrhea. B: RDHA - Reverse direct hemagglutination assay - This test is not typically used for these specific infections. D: Immunoblot analysis - While Immunoblot analysis is a useful confirmatory test for certain infections, it is not the primary method for detecting toxoplasmosis or chronic gonorrhea.

Correct Answer: D

Rationale: The correct answer is D: Innate immunity (natural resistance). Innate immunity refers to the non-specific defense mechanisms that act against a variety of infectious agents. This includes physical barriers like skin and mucous membranes, as well as cellular components like phagocytes and natural killer cells. Adaptive immunity (A) is specific and involves the production of antibodies and immune memory (B), which are not part of the initial non-specific response. Antibodies (C) are part of the adaptive immune response and are produced in response to specific pathogens, not part of the non-specific innate defense factors.

Correct Answer: C

Rationale: The correct answer is C because plasmids do not encode essential bacterial properties. They are non-essential, extra-chromosomal DNA molecules that can replicate independently within bacterial cells. Plasmids mainly contain genes for antibiotic resistance, genetic transfer, and other specific functions. Choice A is correct as many plasmids do carry antibiotic resistance genes. Choice B is also accurate as plasmids are indeed smaller, circular, and exist outside the bacterial chromosome. Choice D is true as plasmids can facilitate bacterial conjugation, allowing the transfer of genetic material between bacteria.

Correct Answer: A

Rationale: The correct answer is A: Carbenicillin disodium. Carbenicillin is a semisynthetic penicillin that has marked activity against Pseudomonas aeruginosa. This is due to its extended spectrum of activity and increased stability against beta-lactamases produced by Pseudomonas aeruginosa. Carbenicillin is commonly used to treat infections caused by this bacterium. Choice B: Benzylpenicillin (Penicillin G) has limited activity against Pseudomonas aeruginosa. Choice C: Methicillin is not effective against Pseudomonas aeruginosa. Choice D: Oxacillin also has limited activity against Pseudomonas aeruginosa. In summary, Carbenicillin is the correct choice due to its marked activity against Pseudomonas aeruginosa compared to the other penicillins listed.