Microbiology Chapter 11 Test Bank

Correct Answer: A

Rationale: The correct answer is A: Toxoplasma. Toxoplasma gondii causes Toxoplasmosis, a protozoan disease that can affect the brain and lead to vision loss. The halfmoon-shaped unicellular organisms with pointed ends described in the blood analysis are characteristic of Toxoplasma parasites. Toxoplasma infection commonly occurs through ingestion of contaminated food or water, or contact with infected cat feces. Leishmania causes Leishmaniasis, Lamblia causes Giardiasis, Amoeba causes Amebiasis, and Trichomonad causes Trichomoniasis, none of which match the symptoms and blood analysis findings described in the question.

Correct Answer: C

Rationale: The correct answer is C, transplacental mechanism. Listeria monocytogenes can cross the placenta, infecting the fetus during pregnancy. This mechanism allows the bacteria to be transmitted from mother to baby in utero. Alimentary mechanism (A) involves ingestion of contaminated food, not direct transfer between individuals. Transmission (B) is a broad term that doesn't specify the specific route of Listeria transmission. Physical contact (D) is not a common mode of Listeria transmission compared to transplacental transmission in the case of maternal-fetal infection.

Correct Answer: A

Rationale: The correct answer is A because bacterial conjugation involves the transfer of genetic material through a sex pilus from a donor bacterium to a recipient bacterium. This process allows for the exchange of genetic material and can lead to increased genetic diversity within bacterial populations. Option B is incorrect because the uptake of free DNA from the environment is known as transformation, not conjugation. Option C is incorrect as transfer of DNA by bacteriophages is called transduction, not conjugation. Option D is incorrect because binary fission is a form of asexual reproduction in bacteria, not a mechanism for genetic exchange.

Correct Answer: A

Rationale: The correct answer is A: emergence. The term emergence refers to the process of a new infectious disease appearing and spreading within a population. It signifies the initial introduction and establishment of the disease in the new population. Explanation for other choices: B: Adoption does not accurately describe the process of a disease spreading within a new population. C: Inclusion is not a term commonly used to describe the spread of infectious diseases. D: Appearance is too vague and does not capture the complexity of the process of establishment and spreading of an infectious disease.

Correct Answer: A

Rationale: The correct answer is A: Mycobacterium leprae. This bacterium is responsible for causing leprosy because it has a unique ability to infect the skin, nerves, and mucous membranes. It is an acid-fast bacillus that multiplies very slowly, leading to a chronic infection. Clostridium botulinum (choice C) causes botulism, Escherichia coli (choice B) causes various gastrointestinal infections, and Staphylococcus aureus (choice D) causes skin infections and other diseases, but none of these bacteria are associated with leprosy.