The capsule of Bacillus anthracis is made of

Correct Answer: B

Rationale: The capsule of Bacillus anthracis is made of polypeptide. This is because the capsule is composed of a protein-based material that surrounds the bacterium, providing protection and aiding in its virulence. Polysaccharides, lipids, and the absence of capsules are not characteristic of Bacillus anthracis' capsule structure, making choices A, C, and D incorrect, respectively.

Correct Answer: B

Rationale: The correct answer is B: Malarial plasmodiums. The description of crescent bodies with a pointed end, blue cytoplasm, and red nucleus corresponds to the characteristics of Plasmodium species seen in Romanovsky's stain. Plasmodium species are known to cause malaria and have distinct features like the ones described. Incorrect choices: A: Toxoplasmas - Toxoplasma gondii typically appear as tachyzoites or bradyzoites under staining, not crescent bodies. C: Dermotropic leishmania - Leishmania species appear as amastigotes in tissue smears, not crescent bodies. D: Viscerotropic leishmania - Similar to choice C, Leishmania species do not typically present as crescent bodies in stained specimens.

Correct Answer: A

Rationale: The correct answer is A: Pseudomonas aeruginosa. P. aeruginosa is a Gram-negative rod that is oxidase-positive and lactose non-fermenting. The positive oxidase test indicates the presence of cytochrome c oxidase, a characteristic of P. aerugin. E. coli is lactose fermenting. Salmonella and Shigella are also Gram-negative rods, but they are lactose fermenters, unlike the lactose non-fermenting P. aeruginosa.

Correct Answer: A

Rationale: The correct answer is A: Vibrios. Vibrios are gram-negative curved bacteria that are motile and do not form spores or capsules. The description of the bacteria in the question fits the characteristics of Vibrios. Vibrios are commonly found in aquatic environments and some species can cause gastrointestinal infections in humans. B: Spirochetes are also gram-negative curved bacteria, but they are spiral-shaped and have unique axial filaments for motility. The description in the question does not match the characteristics of spirochetes. C: Clostridia are gram-positive, spore-forming bacteria. The question specifically states that the bacteria are gram-negative and do not form spores, ruling out Clostridia. D: Corynebacteria are gram-positive, non-spore-forming bacteria. The description in the question does not match the characteristics of Corynebacteria.

Correct Answer: B

Rationale: During latency, HSV1 exists as episomes in neurons. This is because HSV1 establishes a lifelong latent infection in sensory neurons, where the viral genome remains as a circular episome in the nucleus. This form allows the virus to persist in a dormant state, avoiding detection by the immune system. Choice A is incorrect as HSV1 does not integrate into the host chromosome. Choice C is incorrect as latency is a well-documented phenomenon for HSV1. Choice D is incorrect as the correct answer is B.

Correct Answer: A

Rationale: Ribosomes are the target for antibiotics as they interfere with protein synthesis in bacteria. Aminoglycosides, tetracyclines, macrolides, and lincosamides all target ribosomes by inhibiting protein synthesis at different stages. Beta-lactam antibiotics target cell wall synthesis, not ribosomes. Antifolate compounds, quinolones, and raspicin target DNA synthesis and replication, not ribosomes. Therefore, the correct answer is A as it includes antibiotics that specifically target ribosomes for inhibiting bacterial protein synthesis.

Correct Answer: A

Rationale: The correct answer is A: Streptococcus pyogenes. 1. Gram-positive cocci in chains suggest streptococci. 2. Beta-hemolytic activity indicates Streptococcus pyogenes. 3. Streptococcus pyogenes is commonly associated with sore throat (pharyngitis) and fever. 4. Streptococcus pneumoniae (choice B) is alpha-hemolytic and mainly causes pneumonia. 5. Enterococcus faecalis (choice C) is not typically associated with sore throat. 6. Staphylococcus aureus (choice D) is not commonly beta-hemolytic and is not a typical cause of pharyngitis.

Correct Answer: C

Rationale: The correct answer is C: the hydrolysis of the four-membered ring present in penicillin. Beta-lactamase enzyme catalyzes the hydrolysis of the four-membered beta-lactam ring present in penicillin, rendering the antibiotic ineffective against bacterial cell walls. This enzyme breaks the bond in the beta-lactam ring, thus inactivating the antibiotic. Incorrect choices: A: the final cross-linking reaction to form the bacterial cell wall - This is incorrect as beta-lactamase does not participate in the formation of bacterial cell walls. B: the biosynthesis of the penicillin structure from the amino acid valine and cysteine - This is incorrect as beta-lactamase is not involved in the biosynthesis of penicillin. D: the hydrolysis of the acyl side chain from penicillin structures - This is incorrect as beta-lactamase specifically targets the beta-lactam ring, not the

Correct Answer: A

Rationale: The correct answer is A: protozoans. Pinworms are commonly referred to as Enterobius vermicularis, which are parasitic worms belonging to the phylum Nematoda. Protozoans are single-celled organisms, and pinworms are multicellular worms. Algae are photosynthetic organisms, helminths are parasitic worms (which pinworms fall under), and fungi are eukaryotic organisms that include molds and yeasts. Therefore, protozoans are the correct choice for organisms commonly referred to as pinworms.