openstax microbiology test bank

Correct Answer: A

Rationale: Acyclovir is the correct answer because it is an antiviral drug used to treat herpes simplex and varicella-zoster viruses, not influenza. Tamiflu, Amantadine, and Relenza are used to treat influenza by inhibiting viral replication or easing symptoms. Acyclovir's mechanism of action targets different viruses, making it ineffective for treating influenza.

Correct Answer: A

Rationale: The correct answer is A: Gram staining method. The rationale is as follows: 1. Gentian violet is a primary stain used in the Gram staining procedure to stain the bacterial cells. 2. Lugol's solution is a mordant that helps to fix the crystal violet stain in Gram-positive bacteria. 3. 95% alcohol is used as a decolorizing agent in the Gram staining process to remove the stain from Gram-negative bacteria. 4. Watermagenta is not a standard reagent in the Gram staining method. Therefore, based on the reagents mentioned, the staining method applied in this case is the Gram staining method. Other choices are incorrect: B: Ziehl-Nielsen's - This staining method is used for acid-fast staining, not for lobar pneumonia. C: Romanovsky - This staining method is used for blood smears, not for bacterial staining in pneumonia. D: Neisser - This staining method is not commonly used in routine bacterial staining procedures.

Correct Answer: A

Rationale: The correct answer is A: Treponema pallidum. This bacterium is responsible for causing syphilis due to its unique spiral shape and ability to penetrate mucous membranes. It is transmitted through sexual contact or from mother to child during childbirth. Neisseria gonorrhoeae causes gonorrhea, Chlamydia trachomatis causes chlamydia, and Escherichia coli is a common bacterium found in the gut. Therefore, they are not responsible for syphilis.

Correct Answer: D

Rationale: The correct answer is D: pinocytosis. This is an active transport mechanism where cells engulf fluids or solutes through vesicles. Energy is required to transport substances against a concentration gradient. A is incorrect as pinocytosis is an active process, not passive like pinocytosis. B is incorrect as facilitated diffusion is a passive process that uses carrier proteins to move substances down a concentration gradient. C is incorrect as filtration is a passive process that relies on pressure gradients to move substances across a barrier. Therefore, D is the correct choice as it involves the active transport of substances into the cell.

Correct Answer: A

Rationale: The correct answer is A: Pseudomonas. Pseudomonas bacteria are known to produce yellow-green pigment and a characteristic odor, specifically in meat-peptone agar. This is due to the production of pyoverdin pigment by Pseudomonas. Other choices like Escherichia, Proteus, Klebsiella, and Azotobacter do not typically produce yellow-green pigment or have a characteristic odor in meat-peptone agar. Therefore, based on the specific characteristics mentioned in the question, Pseudomonas is the most appropriate choice.