medical microbiology test bank

Correct Answer: B

Rationale: The correct answer is B: peptidoglycan and calcium dipicolinate. Bacterial endospores are resistant structures formed by certain bacterial species under unfavorable conditions. Peptidoglycan provides structural support, while calcium dipicolinate aids in heat resistance. Lipid bilayers (choice A) are not a primary component. Capsular polysaccharides (choice C) are part of the bacterial capsule, not the endospore. Teichoic acid (choice D) is a component of the cell wall, not the endospore.

Correct Answer: D

Rationale: The correct answer is D because the flu vaccine mainly stimulates systemic immunity, not local immunity. Systemic immunity refers to the immune response throughout the body, while local immunity is specific to a certain area. Choice A is incorrect because the flu vaccine is indeed recommended. Choice B is incorrect as the flu vaccine can be a subunit vaccine, containing only specific antigens. Choice C is incorrect as the flu vaccine is typically administered parenterally, meaning through injection, nasal spray, or oral routes.

Correct Answer: A

Rationale: The correct answer is A: Propionibacterium shermanii. This bacterium is used in the production of certain types of cheese, such as Swiss cheese, to create the characteristic holes and flavor. Propionibacterium produces carbon dioxide gas during fermentation, forming the holes in the cheese. Acetobacter aceti (B) is used in vinegar production. Giardia (C) is a parasite that causes gastrointestinal issues, not used in cheese production. Fusobacterium (D) is a type of bacteria associated with infections in humans, not used in cheese production.

Correct Answer: A

Rationale: The correct answer is A: Clostridium botulinum. This bacterium is responsible for causing botulism due to its production of botulinum toxin, which is one of the most potent neurotoxins known. Clostridium botulinum thrives in anaerobic conditions like improperly canned foods. Staphylococcus aureus (B), Bacillus anthracis (C), and Pseudomonas aeruginosa (D) do not produce the botulinum toxin and are not associated with botulism. Staphylococcus aureus is known for causing food poisoning, Bacillus anthracis for anthrax, and Pseudomonas aeruginosa for various infections, but not botulism.

Correct Answer: A

Rationale: The correct answer is A: chloroplasts. Algae and plant cells have chloroplasts, which are responsible for photosynthesis. This organelle contains chlorophyll, enabling these cells to convert sunlight into energy. Mitochondria (B) are found in all eukaryotic cells, not specific to algae and plants. Vacuoles (C) are present in plant cells but also in other eukaryotic cells. Vesicles (D) are membrane-bound sacs found in all types of cells for transport and storage purposes, not unique to algae and plants. Therefore, A is the correct answer.