microbiology an introduction 13th edition test bank

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: 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: A vaccine strain. Virus Fixe is a specific strain of rabies virus used in the production of rabies vaccines. This strain has been attenuated to be safe for use in vaccines. Choice B, a cell culture, is incorrect as it does not specifically refer to Virus Fixe. Choice C, a wild type of rabies virus, is incorrect as Virus Fixe is not a wild type but a modified strain. Choice D, an infectious disease, is incorrect as Virus Fixe is not a disease but a strain of virus used in vaccines.

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.

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.