mcgraw hill microbiology test bank

Correct Answer: D

Rationale: The correct answer is D because antigens can be composed of lipids, proteins, or polysaccharides. Antigens are molecules that can elicit an immune response in the body. They can be diverse in their chemical composition, leading to the recognition and response by the immune system. Therefore, the correct choice is D as antigens can be any of these chemical components. Choices A, B, and C are incorrect because they each represent a possible chemical composition of antigens, but the flexibility of antigens to be made up of any of these components makes D the most accurate choice.

Correct Answer: B

Rationale: The correct answer is B: Disinfection. Disinfection is not a method for food preservation but rather a process of destroying harmful microorganisms on surfaces. A: Pasteurization involves heating food to kill pathogens, preserving the food. C: Irradiation uses radiation to kill bacteria and parasites, extending shelf life. D: Ultrahigh-temperature pasteurization involves heating food at very high temperatures to extend shelf life. In summary, disinfection is not a method used to preserve food but rather to clean surfaces.

Correct Answer: B

Rationale: The correct answer is B: Outer membrane with lipopolysaccharides. Gram-negative bacteria have an outer membrane that contains lipopolysaccharides, which play a role in pathogenicity and resistance to certain antibiotics. This outer membrane is a distinguishing feature of Gram-negative bacteria, as opposed to Gram-positive bacteria that have a thick peptidoglycan layer. Choices A, C, and D are incorrect because Gram-negative bacteria have a thin peptidoglycan layer, do have a cell wall (although it is different from Gram-positive bacteria), and do not contain teichoic acids.

Correct Answer: C

Rationale: The correct answer is C because "Infectious disease" is a combination of both a clinical term (A) and a term expressing the possibility of developing certain symptoms in an infection (B). Infectious diseases are illnesses caused by pathogenic microorganisms, such as bacteria, viruses, parasites, or fungi, that can spread directly or indirectly from person to person. Therefore, the term encompasses both the clinical aspect of the disease and the potential symptoms that may manifest in an infected individual. Choices A and B alone do not fully capture the comprehensive definition of infectious disease, making C the correct answer. Choice D is incorrect as there is a correct answer in this case.

Correct Answer: C

Rationale: The correct answer is C: Visceral leishmaniasis. This disease is caused by the protozoan parasite Leishmania, which is transmitted by sandfly bites. The symptoms described in the question, such as enlarged liver and spleen, peripheral gland enlargement, and eathy colored skin, are characteristic of visceral leishmaniasis. Amebiasis (choice A) typically presents with gastrointestinal symptoms, Balantidiasis (choice B) is caused by a different parasite and presents with dysentery, and Lambliasis (choice D) is caused by Giardia lamblia and presents with diarrhea.