Method for rapid diagnosis of some viral infections is

Correct Answer: D

Rationale: The correct answer is D because utilizing all three methods—immunofluorescence, viral neutralization reaction, and electron microscopy—provides a comprehensive and rapid diagnosis of various viral infections. Immunofluorescence detects viral antigens directly, viral neutralization reaction demonstrates the presence of specific antibodies, and electron microscopy visualizes viral particles. This combination ensures accurate and quick identification of different viruses. Choices A, B, and C alone may not cover all aspects of viral diagnosis, making them less effective compared to the comprehensive approach of using all three methods.

Correct Answer: A

Rationale: Rationale: Vibrio cholerae produces the exotoxin responsible for severe diarrhea. It causes cholera by disrupting the normal functioning of the intestines. Clostridium botulinum causes botulism, not diarrhea. Streptococcus pyogenes causes strep throat and skin infections. Salmonella enterica causes food poisoning, not severe diarrhea. Therefore, the correct answer is A.

Correct Answer: B

Rationale: The correct answer is B: Family Reoviridae. Reassortment of gene segments occurs in segmented viruses like Reoviruses. In Reoviridae, each segment encodes a specific protein, allowing for reassortment to generate new strains. Togaviridae (A) is a non-segmented virus, not capable of reassortment. Picornaviridae (C) and Paramyxoviruses (D) are also non-segmented viruses, limiting their ability for reassortment. Therefore, the correct choice is B due to the segmented nature of Reoviruses allowing for genetic reassortment.

Correct Answer: A

Rationale: The correct answer is A: Halophiles. Halophiles are bacteria that thrive in high-salinity environments due to their ability to tolerate high salt concentrations. They have adapted mechanisms to maintain osmotic balance and survive in such extreme conditions. Thermophiles (B) thrive in high-temperature environments, not high-salinity. Acidophiles (C) prefer acidic conditions, not high-salinity. Mesophiles (D) grow optimally at moderate temperatures and are not specifically adapted to high-salinity environments.

Correct Answer: B

Rationale: Memory cells are not part of the non-specific immune response because they are a component of the specific immune response. Non-specific immune responses are immediate and target a broad range of pathogens, whereas memory cells are formed after exposure to a specific pathogen to provide a quicker and stronger response upon subsequent exposure. Lysozyme (A), Interferon (C), and Phagocytosis (D) are all part of the non-specific immune response. Lysozyme is an enzyme that destroys bacterial cell walls, interferon helps to inhibit viral replication, and phagocytosis involves the engulfing and destruction of pathogens by phagocytes. These responses are not specific to particular pathogens and are the body's first line of defense.

Correct Answer: D

Rationale: The correct answer is D. Escherichia coli, Salmonella enterica, and Pseudomonas aeruginosa all produce endotoxins that can lead to septic shock. Endotoxins are components of the outer membrane of Gram-negative bacteria that can trigger a systemic inflammatory response, potentially leading to septic shock. E. coli and Salmonella are common causes of bacterial infections that can result in septic shock, while P. aeruginosa is known for causing infections in immunocompromised individuals. Therefore, since all three bacteria produce endotoxins that can lead to septic shock, the correct answer is D.Choices A, B, and C are incorrect because each of these bacteria individually produces endotoxins that can contribute to septic shock.

Correct Answer: A

Rationale: The correct answer is A: decompose hydrogen peroxide. Catalase is an enzyme that breaks down hydrogen peroxide into water and oxygen. This is important in bacteria to protect them from the harmful effects of hydrogen peroxide, a byproduct of metabolism. Choice B is incorrect as peptidoglycan synthesis is not the function of catalase. Choice C is incorrect as oxidative phosphorylation is a metabolic process unrelated to catalase function. Choice D is incorrect as endotoxin production is not a role of catalase.

Correct Answer: A

Rationale: The correct answer is A: Candida. The whitish spots resembling coagulated milk on the mucous membranes are characteristic of oral thrush, a condition caused by Candida species. Candida is a gram-positive oval yeast-like fungus commonly found in the oral cavity. Staphylococci (B) are gram-positive cocci, not yeast-like cells. Diphtheria bacillus (C) causes diphtheria, not oral thrush. Actinomycetes (D) are filamentous bacteria, not yeast-like cells typically seen in oral thrush. Therefore, A is the correct answer based on the clinical presentation and microscopic findings.

Correct Answer: C

Rationale: The correct answer is C: nucleotides. Nucleotides are the structural units of nucleic acids, consisting of a nitrogenous base, a sugar molecule, and a phosphate group. The nitrogenous base can be adenine, thymine, cytosine, guanine, or uracil. Histones (B) are proteins that DNA wraps around in chromosomes, not structural units of nucleic acids. Nucleosides (A) are composed of a nitrogenous base and a sugar molecule but lack the phosphate group present in nucleotides. N-bases (D) is not a recognized term in biology and does not accurately describe the structural units of nucleic acids.