microbiology an introduction 13th edition test bank -Nurselytic

Correct Answer: D

Rationale: The correct answer is D because Mycobacterium tuberculosis is a straight or slightly curved rod with occasional polymorphism. This bacterium does not conform to the characteristics of gram-negative coccus (
A), gram-positive coccus (
B), or gram-negative rod (
C). Mycobacterium tuberculosis is characterized by its unique cell wall composition, which includes high lipid content and mycolic acids, contributing to its acid-fast staining property. The other choices are incorrect because they do not accurately describe the morphology of Mycobacterium tuberculosis.

Correct Answer: D

Rationale: The correct answer is D because antibody diversity is generated by rearrangements of DNA encoding variable regions of heavy and light chains (choice
A) and by the combination of different heavy and light chains that form the antigen binding site (choice
B).


Step 1: DNA rearrangements create different variable regions in heavy and light chains.

Step 2: Combination of different heavy and light chains leads to unique antigen binding sites.

Step 3: This diversity allows antibodies to bind to different epitopes on the same antigen.

Step 4:
Choice C is incorrect as antibodies do not physically change shape to bind different epitopes.

Correct Answer: A

Rationale: The correct answer is A: Escherichia coli. E. coli is the most common bacteria responsible for causing urinary tract infections due to its ability to adhere to the urinary tract lining and multiply rapidly. It is a normal inhabitant of the gut and can enter the urinary tract through improper hygiene practices. Salmonella enterica and Neisseria gonorrhoeae are typically associated with other infections like food poisoning and gonorrhea, respectively. Mycobacterium tuberculosis causes tuberculosis, not urinary tract infections. Thus, based on its prevalence and pathogenicity in the urinary tract, E. coli is the correct choice.

Correct Answer: B

Rationale: The correct answer is B because intensity, frequency, and thickness of the sample are key factors that determine the effects of different kinds of radiation. Intensity refers to the amount of energy carried by the radiation, frequency indicates the number of waves per unit time, and the thickness of the sample affects the penetration of radiation. These factors directly influence the interactions of radiation with matter, such as ionization and heating effects.

A is incorrect because wavelength is not a major factor in determining the effects of radiation. C is incorrect because distance and nature of the sample are not as significant as intensity, frequency, and thickness. D is incorrect because chemical composition and shielding, while important in certain contexts, are not the primary factors affecting the effects of radiation.

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.