Mesophylic bacteria are with temperature optimum:

Correct Answer: A

Rationale: The correct answer is A (25-37 °C) because mesophilic bacteria thrive best at moderate temperatures typical of most environments, making 25-37 °C their optimum range. This range allows for optimal enzyme activity and growth. Choice B (55-65 °C) is incorrect as it is more suitable for thermophilic bacteria. Choice C (15-18 °C) is too low for mesophiles to thrive efficiently. Choice D (38-45 °C) is too high and is more suitable for thermophiles. Ultimately, the correct answer aligns with the typical temperature range where mesophilic bacteria are most active and abundant.

Correct Answer: A

Rationale: The correct answer is A: Nucleoid. The bacterial genome is located in the nucleoid, a region within the bacterial cell where the genetic material is condensed and organized. This structure is not the same as a nucleus found in eukaryotic cells. The other choices (B: Nucleotide and C: ATP) are incorrect because nucleotide refers to a building block of DNA or RNA, and ATP is a molecule used for energy transfer in cells, neither of which specifically houses the bacterial genome. Choice D: None of the above is incorrect as well, as the correct term for the compact structure containing the bacterial genome is the nucleoid.

Correct Answer: D

Rationale: The correct answer is D: Rifampicin. Rifampicin is a first-line antibiotic for treating pulmonary tuberculosis due to its high efficacy against Mycobacterium tuberculosis. It works by inhibiting bacterial RNA synthesis. Furasolidone (A) is not commonly used for tuberculosis, Bactrim (B) is not a first-line drug for tuberculosis, and Streptocide (C) is not as effective as Rifampicin.

Correct Answer: A

Rationale: Cell-mediated immunity plays a crucial role in combating infections with intracellular pathogens by activating T cells to directly kill infected cells. Facultative and obligate intracellular pathogens, such as viruses and some bacteria, require cell-mediated immunity for effective clearance. Option A is correct due to the specificity of this immune response. Choices B, C, and D are incorrect as they are primarily associated with humoral immunity involving antibodies and not T cell responses against intracellular pathogens.

Correct Answer: B

Rationale: The correct answer is B: Vibrio cholerae. Cholera is caused by this specific bacterium. Vibrio cholerae produces a toxin that leads to severe diarrhea and dehydration. Salmonella typhi causes typhoid fever, Escherichia coli can cause various infections but not cholera, and Shigella dysenteriae causes dysentery, not cholera. Therefore, the correct choice is B.