microbiology an introduction 13th edition test bank

Correct Answer: A

Rationale: Step 1: Vibrio cholerae is a bacterium known to cause cholera, a foodborne illness transmitted through contaminated water. Step 2: Cholera outbreaks are often linked to unsanitary water sources, making Vibrio cholerae the correct choice. Step 3: Clostridium difficile causes gastrointestinal infections, not typically associated with contaminated water. Step 4: Mycobacterium tuberculosis causes tuberculosis, a respiratory disease, not related to foodborne illnesses. Step 5: Neisseria gonorrhoeae is a sexually transmitted bacterium, not linked to foodborne illnesses from contaminated water.

Correct Answer: C

Rationale: Rationale: 1. The male reproductive system is considered sterile as it does not have a natural microbiota. 2. Any presence of microorganisms in this system could indicate an infection or disease. 3. Therefore, choice C, sterile with no normal flora, is the best characterization. Summary: A: Incorrect - The male reproductive system does not typically have gram-positive rods. B: Incorrect - Acid-fast rods are not part of the normal flora in the male reproductive system. D: Incorrect - The male reproductive system does not typically have gram-positive spore formers.

Correct Answer: B

Rationale: Step 1: The description of microorganisms resembling tennis racket indicates Corynebacterium diphtheriae, the causative agent of diphtheria. Step 2: Diphtheria is a bacterial infection that can cause severe respiratory and systemic symptoms. Step 3: Botulism is caused by Clostridium botulinum, not tennis racket-shaped microorganisms. Step 4: Typhoid fever is caused by Salmonella typhi, which does not resemble tennis rackets. Step 5: Salmonellosis is caused by various Salmonella species, which also do not have the described tennis racket appearance.

Correct Answer: A

Rationale: The correct answer is A: proteins. Enzymes are mostly composed of proteins due to their complex structure and specific amino acid sequences that are essential for their catalytic activity. Proteins have active sites that bind to substrates and facilitate chemical reactions. Lipids (B), nucleic acids (C), and carbohydrates (D) do not possess the necessary properties and structures to function as enzymes. Lipids serve as energy storage molecules and cell membrane components, nucleic acids store genetic information, and carbohydrates are primarily used for energy production.

Correct Answer: A

Rationale: The correct answer is A because differential growth media, such as Endo agar and MacConkey agar, contain specific indicators or substrates that allow for the differentiation of microorganisms based on their metabolic properties. For example, Eosin methylene blue agar differentiates between lactose fermenting and non-fermenting bacteria based on color changes. Levine's formulation is selective for Gram-negative bacteria due to bile salts and crystal violet. In contrast, the other choices do not have specific indicators for differentiation among microorganisms. Lowenstein-Jensen and SS agar are selective media for mycobacteria and Salmonella/Shigella species, respectively. ACA and BPLS agar are selective but not differential, and Nutrient agar and Peptone water are general-purpose media without differential properties.