When a smear is stained by Burri-Gins method a mucous structure that is tightly bound with the cellular wall of bacteria and has well-defined outer boundaries can be detected. This element of a bacteria cell is called:

Correct Answer: A

Rationale: The correct answer is A: Capsule. A capsule is a mucous structure tightly bound to the bacterial cell wall with distinct outer boundaries. This structure helps bacteria evade the host immune system, resist desiccation, and adhere to surfaces. In contrast, spores are resistant structures formed by certain bacteria for survival, filaments are long chains of bacterial cells, and ribosomes are cellular organelles responsible for protein synthesis. Therefore, based on the characteristics described in the question, the most appropriate choice is A: Capsule.

Correct Answer: C

Rationale: The correct answer is C: Survival. Bacterial spores are specialized structures that bacteria form to survive harsh conditions such as extreme temperatures or lack of nutrients. Spores are not used for protection against phagocytosis (A) as they are dormant structures and not actively involved in defense mechanisms. They are not for reproduction (B) as spores are a form of bacterial reproduction but not the primary purpose of spore formation. Spores do not serve as nutrient storage (D) as they are mainly used for survival during unfavorable conditions.

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: A

Rationale: The correct answer is A because adaptive immunity is not mainly observed in the skin and mucous membranes. Adaptive immunity is a systemic response that involves specific immune cells and antibodies targeting specific pathogens. It develops immune memory (B), meaning it can recognize and respond faster upon re-exposure to the same pathogen. Adaptive immunity also has specificity (C), as it can target specific antigens. Lastly, adaptive immunity is not evolutionarily newer in comparison to innate immunity (D), as both systems have co-evolved to provide comprehensive protection against pathogens.

Correct Answer: D

Rationale: The correct answer is D (All of the above) because all three bacteria (Clostridium botulinum, Escherichia coli, Salmonella enterica) are known to cause foodborne infections. Clostridium botulinum can lead to botulism, E. coli can cause various gastrointestinal illnesses, and Salmonella enterica is a common cause of food poisoning. Each bacterium has specific mechanisms that result in foodborne illnesses. Choices A, B, and C are incorrect because each bacterium mentioned is associated with causing foodborne infections, making them collectively the correct answer.

Correct Answer: A

Rationale: The correct answer is A: Treponema. The characteristics described match Treponema pallidum, the causative agent of syphilis. Treponema has long, spiral shape with 8-12 regular coils. Leptospira (B) is a spirochete but has fewer coils and causes leptospirosis. Borrelia (C) is another spirochete but typically has irregular coils and causes Lyme disease. Vibrios (D) are curved rods and not spirochetes.

Correct Answer: B

Rationale: The correct answer is B: Order. The suffix -virales is used in virology to denote the order level in the taxonomy of viruses. Orders are higher taxonomic ranks compared to species, family, and genus. The suffix -virales is specifically assigned to virus orders, making choice B the correct one. The other choices (A, C, D) are incorrect because the suffix -virales does not apply to species, family, or genus in the taxonomic classification of viruses.

Correct Answer: C

Rationale: The correct answer is C (coli index of 250 and coli titer of 4). The coli index is calculated by multiplying the number of colonies by the reciprocal of the volume filtered, which gives 2 colonies x (1/0.5 L) = 4. The coli titer is obtained by dividing the volume filtered by the number of colonies, which gives 0.5 L / 2 colonies = 0.25 L or 250 ml. This indicates the concentration of coliform bacteria in the water sample. Choice A (4 and 250) is incorrect because it has the correct coli index but the values are reversed for coli index and coli titer. Choice B (2 and 500) is incorrect as it provides the correct coli titer value but the values are reversed for coli index and coli titer. Choice D (500 and 2) is incorrect because it reverses the values for both coli index and coli titer.

Correct Answer: C

Rationale: The correct answer is C: Mumps. Group II diseases are vaccine-preventable diseases that are communicable and can cause outbreaks. Mumps fits this criteria as it is preventable through vaccination, easily transmitted through respiratory droplets, and can lead to outbreaks in communities. Anthrax (A) is a zoonotic disease, Lyme disease (B) is transmitted by ticks, and Smallpox (D) has been eradicated.