Adenoviral infections are restricted only to the upper respiratory tract:

Correct Answer: B

Rationale: The correct answer is B: FALSE. Adenoviral infections are not restricted only to the upper respiratory tract; they can also affect the gastrointestinal tract, eyes, and other organs. Adenoviruses are known to cause a wide range of illnesses beyond just respiratory infections. Therefore, option B is correct. Option A is incorrect because it states that adenoviral infections are restricted to the upper respiratory tract, which is not true. Option C is incorrect because there is no circumstance where adenoviral infections are solely limited to the upper respiratory tract. Option D is also incorrect as the correct answer is B.

Correct Answer: D

Rationale: The correct answer is D: All of the above. Tuberculosis, Q-fever, and Legionnaires disease all can infect the respiratory tract. Tuberculosis is a bacterial infection affecting the lungs, Q-fever is caused by a bacterium that primarily affects the lungs, and Legionnaires disease is a severe form of pneumonia. All three diseases specifically target the respiratory system, making them the correct choices. Choices A, B, and C are incorrect because each of them individually infects the respiratory tract, not just one or two of them.

Correct Answer: C

Rationale: The correct answer is C because F pili are proteins on the F+ donor cell that are attached to specific receptors on the recipient cell's cell wall. This is essential for the transfer of genetic material during conjugation. Choice A is incorrect because F pili are not made up of nucleotides, but rather proteins. Choice B is incorrect because F pili are not transferred to the recipient cell itself, but they facilitate the transfer of genetic material. Choice D is incorrect because F pili are not part of the recipient cell, but rather part of the donor cell for attachment to the recipient cell.

Correct Answer: C

Rationale: The correct answer is C: Replication. In DNA replication, the original DNA molecule is unwound and each strand serves as a template to synthesize a new complementary strand. This results in two identical copies of the original DNA molecule. Translation (A) is the process of synthesizing proteins from mRNA. Transcription (B) is the process of synthesizing mRNA from DNA. Cell division (D) is the process of a cell dividing into two daughter cells, not specifically producing identical DNA copies. Therefore, replication is the correct answer as it specifically refers to the process of copying DNA to produce two identical copies.

Correct Answer: B

Rationale: The correct answer is B because the complement fixation test is a serological test that detects the presence of specific antibodies or antigens in a patient's serum. It works by measuring the ability of antibodies to fix complement proteins. Choice A is incorrect because the complement fixation test typically involves several steps, not necessarily three. Choice C is incorrect as standardized complement proteins are commonly used in this test. Choice D is incorrect because sheep red blood cells are not essential for performing the complement fixation test.