openstax microbiology test bank

Correct Answer: A

Rationale: The correct answer is A because lipophilization is the process of removing water from cells under deep vacuum in a frozen state. Dehydration of the cell at a low temperature helps to preserve the cellular structure and components. Choice B is incorrect as hydration does the opposite of what lipophilization aims to achieve. Choice C is incorrect as lipophilization does not involve enriching cells with proteins. Choice D is incorrect as lipophilization does not involve removing protein content from cells.

Correct Answer: B

Rationale: The correct answer is B: placenta. The placenta is a highly specialized structure that forms during pregnancy and serves as a barrier, protecting the fetus from harmful microorganisms that could potentially harm the developing baby. It facilitates the exchange of nutrients, oxygen, and waste between the mother and fetus while preventing the passage of most bacteria and viruses. The uterus (A) is the organ where the fetus develops, but it does not have the specific protective functions of the placenta. The vagina (C) is the birth canal and does not provide protection from microorganisms for the fetus. The mammary gland (D) is responsible for producing milk after birth and is not directly involved in protecting the fetus from microorganisms during pregnancy.

Correct Answer: A

Rationale: The correct method of laboratory diagnostics for suspected malaria is blood examination. Malaria is diagnosed by detecting the presence of the Plasmodium parasite in the patient's blood. This can be done through microscopy to identify the parasite in a blood smear or through rapid diagnostic tests (RDTs) that detect specific antigens produced by the parasite. Blood examination allows for the direct visualization of the parasite, making it the most accurate method for diagnosing malaria. Immunological tests, stool examination, and urine examination are not suitable for diagnosing malaria as the parasite primarily resides in the red blood cells. Stool and urine examinations are more commonly used for diagnosing gastrointestinal or urinary tract infections, respectively.

Correct Answer: D

Rationale: The correct answer is D because the rubella virus has icosahedral symmetry, meaning it has a spherical shape with 20 equilateral triangular faces. This symmetry is common in many viruses and allows for efficient packaging of genetic material. Choice A is incorrect because the rubella virus does have glycoprotein spikes on its surface. These spikes help the virus attach to host cells. Choice B is incorrect because the rubella virus does have an envelope derived from the host cell membrane. This envelope plays a role in viral entry into host cells. Choice C is incorrect because the rubella virus is an ssRNA virus, not ssDNA. Its genetic material is single-stranded RNA, not DNA. In summary, the rubella virus has icosahedral symmetry and possesses glycoprotein spikes, an envelope, and ssRNA genetic material, making choices A, B, and C incorrect.

Correct Answer: B

Rationale: The correct answer is B: Protection against phagocytosis. The bacterial capsule is a protective layer outside the cell wall that helps bacteria evade phagocytosis by the host immune system. It acts as a physical barrier against immune cells like macrophages and neutrophils, allowing the bacteria to survive and multiply in the host. Energy production (A), DNA replication (C), and protein synthesis (D) are essential cellular functions but are not directly associated with the major function of the bacterial capsule, which is protection against phagocytosis.