microbiology a systems approach test bank

Correct Answer: D

Rationale: Certainly! The correct answer is D: Pertussis exotoxin. Pertussis toxin primarily affects the respiratory system causing whooping cough. It does not directly target the nervous system like the other toxins listed. Tetanospasmin causes muscle spasms, Diphtheria exotoxin affects the heart and nerves, and Botulinum exotoxin causes paralysis by blocking neurotransmitter release. Therefore, Pertussis exotoxin is the only toxin among the options that does not manifest with neurological symptoms.

Correct Answer: A

Rationale: The correct answer is A: TRUE. B-lymphocyte antigen receptors are made by proteins called immunoglobulins. These proteins are essential for recognizing and binding to specific antigens. They play a crucial role in the immune response. Choice B is incorrect because B-lymphocyte antigen receptors are indeed made by proteins. Choice C is incorrect as well because in this case, the correct answer is that the receptors are made by proteins. Choice D is also incorrect as the receptors are made by proteins.

Correct Answer: A

Rationale: The correct answer is A: Parvoviridae. Parvoviruses are DNA viruses, as their genetic material is composed of DNA. This distinguishes them from RNA viruses like Picornaviridae, Astroviridae, and Togaviridae. Parvoviruses replicate in the host cell nucleus, further confirming their DNA nature. Therefore, based on their DNA composition and replication process, Parvoviridae is the correct choice.

Correct Answer: B

Rationale: The correct answer is B: Escherichia coli. E. coli is the most common cause of UTIs due to its ability to colonize the urinary tract. It possesses adhesive factors that enable it to attach to the bladder and cause infection. Clostridium tetani causes tetanus, Mycobacterium leprae causes leprosy, and Bacillus anthracis causes anthrax, none of which are typically associated with UTIs. E. coli's prevalence in the gut and its pathogenic mechanisms make it the leading cause of UTIs.

Correct Answer: A

Rationale: The correct answer is A: Amebiasis. Amebiasis is caused by the parasite Entamoeba histolytica, presenting with symptoms like acute abdominal pain, bloody diarrhea with mucus, and inconstant shape organisms seen in fecal smear. The presence of erythrocytes supports the diagnosis due to the parasite's ability to invade intestinal mucosa causing bleeding. Choice B (Lambliasis) presents with different symptoms like steatorrhea and fatigue. Choice C (Schistosomiasis) is mainly associated with liver and urinary symptoms. Choice D (Intestinal trichomoniasis) commonly presents with watery diarrhea and does not typically cause bloody stools. Therefore, based on the patient's symptoms and fecal smear findings, Amebiasis is the most likely diagnosis.