The most common bacterial nonsexually transmitted infection of the male reproductive system is:

Correct Answer: B

Rationale: The correct answer is B: prostatitis. Prostatitis is the most common bacterial infection affecting the male reproductive system. It is characterized by inflammation of the prostate gland due to bacterial infection. Symptoms include pain in the pelvic area, difficulty urinating, and fever. Cystitis (A) is a bladder infection, not specific to the male reproductive system. Mastitis (C) is inflammation of the breast tissue, which is not related to the male reproductive system. Nephritis (D) is inflammation of the kidneys, which is also not specific to the male reproductive system.

Correct Answer: A

Rationale: The correct answer is A: Gin's stain method. Gin's stain method is specifically used to detect capsules of bacteria. This method involves staining the bacteria with crystal violet and copper sulfate, which highlights the capsules as a clear halo around the stained bacterial cells. Ziehl-Neelsen's stain is used for acid-fast bacteria like Mycobacterium tuberculosis, Neisser's stain is for detecting Neisseria species, and Gram's stain is for differentiating bacteria based on their cell wall composition (Gram-positive vs. Gram-negative). Therefore, choices B, C, and D are incorrect for this scenario.

Correct Answer: B

Rationale: The correct answer is B because bacteria synthesize enzymes with various nature and action. This is true because bacteria can produce a wide range of enzymes to carry out different functions such as metabolism, cell wall synthesis, and nutrient acquisition. Option A is incorrect because bacteria do not synthesize identical enzyme sets due to their diverse functions. Option C is incorrect as bacteria and viruses have distinct enzyme profiles. Option D is incorrect as viruses typically have a narrower range of enzymes compared to bacteria. Therefore, the variability in enzyme types and actions produced by bacteria supports the correctness of option B.

Correct Answer: D

Rationale: The correct answer is D: lyases. Lyases are enzymes that catalyze the breaking of chemical bonds without the addition of water. They can remove functional groups from substrates or add functional groups to double bonds without the use of water. A: Oxidoreductases involve the transfer of electrons. B: Transferases transfer functional groups from one molecule to another. C: Hydrolases catalyze the breaking of bonds by adding water.

Correct Answer: C

Rationale: The correct answer is C: Respiratory tract. The respiratory tract is likely the most frequently used portal of entry for pathogens because it is constantly exposed to the external environment and has a large surface area lined with mucous membranes that can trap and facilitate the entry of pathogens. Additionally, the respiratory tract serves as a direct pathway for pathogens to reach the bloodstream and other organs. Skin (choice A) is a physical barrier that can prevent pathogen entry, while the gastrointestinal tract (choice B) has acidic pH and enzymes that can kill many pathogens. Conjunctiva (choice D) is a less common portal of entry compared to the respiratory tract due to its smaller surface area and protective mechanisms such as tears.

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: C

Rationale: The correct answer is C because bacteriocins are substances with protein nature, not polysaccharides. Bacteriocins are antimicrobial peptides that kill bacterial cells, mainly those of closely related species or other strains of the same species. Polysaccharides are not typically involved in bacteriocin activity. Therefore, option C is false. Options A, B, and D are true statements supported by the nature and function of bacteriocins.

Correct Answer: A

Rationale: The correct answer is A: nematode. Trichinosis is caused by the roundworm Trichinella spiralis, a type of nematode. Nematodes are multicellular parasites commonly found in raw or undercooked meat. Viruses, bacteria, and fungi do not cause trichinosis. Viruses are not parasitic worms, bacteria are single-celled organisms, and fungi are eukaryotic organisms distinct from nematodes. Therefore, the ingestion of nematodes, not viruses, bacteria, or fungi, leads to trichinosis.

Correct Answer: B

Rationale: Step-by-step rationale: 1. Monotrichous means having a single flagellum at one end. 2. The term "polar" indicates that the flagellum is located at one end of the bacterium. 3. Therefore, bacteria with a single polar flagellum are referred to as monotrichous. 4. Choice A is a typo, as it is the same as the correct answer B. Summary: - Choice A is a typo, as it duplicates the correct answer. - Choice C, amphitrichous, refers to bacteria with a flagellum at each end. - Choice D, peritrichous, describes bacteria with flagella distributed over the entire surface.