Toxoplasma gondii belongs to which group of eukaryotic organisms?

Correct Answer: C

Rationale: Toxoplasma gondii is a protozoan parasite known to cause toxoplasmosis. It belongs to the group of eukaryotic organisms called protozoans because it is a single-celled organism with complex cellular structures. Protozoans are characterized by their ability to move and perform essential functions independently. Algae (choice A) are photosynthetic eukaryotic organisms, fungi (choice B) are non-photosynthetic eukaryotes that include molds and yeasts, and helminths (choice D) are multicellular parasitic worms. Therefore, the correct answer is C because Toxoplasma gondii is a protozoan parasite.

Correct Answer: D

Rationale: The most probable diagnosis is D: Tularemia. Tularemia is a bacterial infection caused by Francisella tularensis. The symptoms described align with tularemia, such as pain in axillary area, fever, shaky gait, coated tongue, frequent pulse, painful lymphatic nodules, and erythematous skin over nodules. The key features pointing towards tularemia are the presence of lymphadenitis in the axillary area and the erythematous, glistering skin over the nodules, which are characteristic of ulceroglandular tularemia. Bubonic plague (A) presents with painful, swollen lymph nodes called buboes but typically lacks the erythematous skin findings. Acute purulent lymphadenitis (B) usually presents with pus-filled lymph nodes but does not typically cause shaky gait or coated tongue. Lymphogranulomatosis (C) is a term for Hodgkin's lymphoma, which does not

Correct Answer: B

Rationale: The correct answer is B: Gram-negative bacteria. Gram-negative bacteria have an outer membrane containing lipopolysaccharides (LPS). In the Gram staining technique, these bacteria appear pink/red due to the thin peptidoglycan layer, which allows the crystal violet stain to be washed out, revealing the safranin counterstain. Gram-positive bacteria (choice A) have a thick peptidoglycan layer but lack an outer membrane with LPS. Choice C is incorrect since only Gram-negative bacteria possess LPS in their outer membrane. Choice D is incorrect as all bacteria can be classified as either Gram-positive or Gram-negative based on their cell wall structure.

Correct Answer: C

Rationale: Rationale: 1. Psychrophilic: Grow best in cold temperatures 2. Mesophilic: Grow best in moderate temperatures 3. Thermophilic: Grow best in high temperatures - Choice A is incorrect as "thermophobic" is not a recognized term. - Choice B is incorrect as "psychophobic" is not a recognized term. - Choice D is incorrect as "mesophobic" is not a recognized term.

Correct Answer: A

Rationale: The correct answer is A: Tetanus. The patient's symptoms of muscle contractions, fever, and wound history suggest tetanus, caused by Clostridium tetani bacteria commonly found in soil. The spastic muscle contractions around the wound are classic for tetanus due to the neurotoxin produced by the bacteria. General weakness and headache are also common symptoms. B: Anthrax is unlikely as it presents with different symptoms such as skin lesions, respiratory symptoms, and gastrointestinal symptoms. C: Erysipelas is characterized by red, swollen patches on the skin, not consistent with the symptoms described. D: Gram-positive is not a specific diagnosis but a broad category of bacteria. Tetanus is caused by Clostridium tetani, which is a Gram-positive bacterium, but this choice does not provide a specific infection diagnosis.

Correct Answer: B

Rationale: Step-by-step rationale: 1. Filamentous spiral nucleocapsid is characteristic of Filoviridae, such as Ebola virus. 2. Linear unsegmented single strand (-) RNA is a key feature of Filoviridae genomes. 3. The lipid bilayer membrane of cellular origin is found in Filoviridae viruses. 4. Therefore, the correct answer is B (Filoviridae) due to the alignment of all three morphological features. Summary: - A (Picornaviridae): Has an icosahedral capsid, not filamentous spiral. - C (Orthomyxoviridae): Has a segmented genome, not linear unsegmented. - D (Togaviridae): Has a spherical capsid, not filamentous spiral.

Correct Answer: C

Rationale: The correct answer is C because Marburg virus and Ebola virus belong to the Filoviridae family. These viruses are characterized by their filamentous shape and are known to cause severe hemorrhagic fever in humans. Both viruses have caused outbreaks with high mortality rates. Choice A (Lassa virus and lymphocytic choriomeningitis viruses) are not part of the Filoviridae family. They belong to the Arenaviridae family, which also includes viruses that cause hemorrhagic fevers. Choice B (Chikungunya virus and Sindbis virus) are arboviruses belonging to the Togaviridae family, which are not related to the Filoviridae family. Choice D (Crimean-Congo virus and Hantaan virus) are part of the Nairoviridae and Hantaviridae families, respectively, and not the Filoviridae family.

Correct Answer: B

Rationale: The correct answer is B: microvilli. Pili are hair-like structures found on the surface of some bacteria, while microvilli are microscopic cellular projections that increase surface area for absorption in cells like intestinal cells. Pili are involved in bacterial adhesion, while microvilli are important for nutrient absorption. Therefore, the correct answer is B. Incorrect choices: A: Fimbriae are short, thin appendages found on the surface of some bacteria, mainly used for adhesion. C: Cilia are hair-like structures found on the surface of some eukaryotic cells, often involved in movement or sensory functions. D: Flagella are long, whip-like appendages used for bacterial motility.

Correct Answer: B

Rationale: The correct answer is B because Haemophilus influenzae, Streptococcus pneumoniae, and Neisseria meningitidis are the most common causative agents of bacterial meningitis. Haemophilus influenzae is often seen in children, Streptococcus pneumoniae is the most common in adults, and Neisseria meningitidis is common in adolescents and young adults. Choice A is incorrect because although Streptococcus group B and Listeria monocytogenes can cause meningitis, E. Coli K1 is not a common causative agent. Choice C is incorrect because Staphylococcus aureus and Pseudomonas aeruginosa are not typically associated with bacterial meningitis. Choice D is incorrect as there are known causative agents for bacterial meningitis.