microbiology an introduction test bank

Correct Answer: A

Rationale: The correct answer is A: cryophiles. Psychrophiles are microorganisms that thrive in cold temperatures. The prefix "cryo-" means cold, which accurately describes the environment in which these organisms grow. Choice B, thermophiles, are organisms that thrive in high temperatures. Choice C, mesophiles, grow best at moderate temperatures. Choice D, psychrotrophs, are organisms that can grow at refrigeration temperatures but have an optimal growth temperature range different from psychrophiles.

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: A

Rationale: Step-by-step rationale: 1. Blue-green pigment + fruity odor are characteristic of Pseudomonas aeruginosa. 2. P. aeruginosa is a Gram-negative bacterium commonly associated with wound infections. 3. P. aeruginosa is known for its ability to produce pyocyanin (blue-green pigment) and a sweet, fruity odor. 4. Other choices like E. coli, K. pneumoniae, and P. mirabilis do not typically produce blue-green pigment or fruity odor. 5. Therefore, based on the characteristics observed, the likely causative agent is Pseudomonas aeruginosa. Summary of other choices: - Escherichia coli: Does not produce blue-green pigment or fruity odor. - Klebsiella pneumoniae: Does not typically produce blue-green pigment or fruity odor. - Proteus mirabilis: Does not produce blue-green pigment or fruity odor.

Correct Answer: B

Rationale: The correct answer is B: Corynebacterium diphtheriae. This bacterium produces a toxin that causes diphtheria. It forms a grayish membrane in the throat, leading to difficulty breathing. Bacillus anthracis (Choice A) causes anthrax, Streptococcus pneumoniae (Choice C) causes pneumonia, and Escherichia coli (Choice D) causes various infections but not diphtheria.

Correct Answer: A

Rationale: The correct answer is A: Botulism. Botulism is caused by the toxin produced by Clostridium botulinum bacteria found in improperly preserved or canned foods. The symptoms described align with botulism, such as difficulty swallowing and breathing due to muscle paralysis. The tennis racket appearance seen under microscopy corresponds to the characteristic appearance of Clostridium botulinum spores. The other choices can be ruled out based on the clinical presentation and microscopy findings. Cholera typically presents with severe watery diarrhea, Nontyphoidal Salmonella infection with fever and gastrointestinal symptoms, and Typhoid fever with high fever and abdominal pain. Therefore, the most likely diagnosis in this case is botulism.