microbiology an introduction 13th edition test bank

Correct Answer: B

Rationale: The correct answer is B: slime mold. Plasmodium is a type of slime mold, specifically a parasitic protist that causes malaria in humans. Slime molds are a group of organisms that share characteristics of both fungi and protozoa. Plasmodium does not belong to the other categories listed: A) protozoan refers to a broad category of single-celled eukaryotic organisms, C) spirochetes are a type of bacteria, and D) helminths are parasitic worms. Therefore, the correct classification for Plasmodium is slime mold.

Correct Answer: A

Rationale: The correct answer is A: Staphylococcus epidermidis. Step 1: Gram-positive cocci in clusters suggest staphylococci. Step 2: Catalase-positive and coagulase-negative narrows it down to Staphylococcus epidermidis, as it is catalase-positive and coagulase-negative. Staphylococcus aureus (B) is catalase-positive and coagulase-positive. Streptococcus pyogenes (C) is catalase-negative. Enterococcus faecalis (D) is catalase-negative and coagulase-negative.

Correct Answer: A

Rationale: The correct answer is A: infants. Staphylococcal scalded skin syndrome is most common in infants because their immune systems are not fully developed, making them more susceptible to Staphylococcus aureus infections. This bacteria produces exotoxins that cause the skin to blister and peel, characteristic of the syndrome. Adolescents, young adults, and the elderly have more mature immune systems, making them less vulnerable to this specific infection. Therefore, infants are at a higher risk for developing Staphylococcal scalded skin syndrome compared to other age groups.

Correct Answer: D

Rationale: The correct answer is D: Mesosomes. Mesosomes are infoldings of the prokaryotic cytoplasmic membrane that play a role in cell division and respiration. This structure is not found in eukaryotic cells. Cristae (A) are infoldings of the mitochondrial inner membrane in eukaryotic cells. Granum (B) refers to stacks of thylakoid membranes in chloroplasts. Flagella (C) are whip-like structures used for movement and are not related to cytoplasmic membrane invaginations. Therefore, the correct answer is D as mesosomes are unique to prokaryotic cells and are involved in various cellular processes.

Correct Answer: A

Rationale: The most probable diagnosis is Tetanus (Choice A) based on the symptoms described. Tetanus is characterized by muscle stiffness, difficulty opening the mouth (trismus), muscle spasms, and convulsions. The progression of symptoms from muscle tension to generalized convulsions every 10-15 min is classic for tetanus. Tetania (Choice B) is similar but typically presents with more subtle muscle contractions rather than convulsions. Meningoencephalitis (Choice C) presents with fever, headache, and altered mental status, not the muscle symptoms described. Hemorrhagic stroke (Choice D) presents with sudden onset neurological deficits like weakness or sensory changes, not the muscle symptoms described.