mastering microbiology test bank

Correct Answer: A

Rationale: The correct answer is A: general-purpose hoods. Bypass fume hoods are designed to handle a wide range of chemical fumes and vapors, making them suitable for various types of experiments and processes. They are not specifically designed for radioisotopes (B), perchloric acid (C), or biological materials (D). Therefore, A is the correct choice for bypass fume hoods.

Correct Answer: B

Rationale: The correct answer is B: Movement of the bacterial cell. Bacterial flagella are whip-like appendages that enable bacteria to move towards nutrients or away from harmful substances. This movement is essential for survival, dispersal, and colonization. Choice A is incorrect because attachment is primarily mediated by other structures like pili. Choice C is incorrect as protein synthesis occurs inside the cell and is not directly related to flagella. Choice D is incorrect as nutrient absorption is typically carried out through specific channels or transport systems, not by flagella.

Correct Answer: A

Rationale: Flagella are the correct answer because they are long, whip-like structures that aid in bacterial movement towards or away from chemical stimuli. They rotate like propellers, allowing the bacterium to navigate its environment. Pili are used for attachment, not movement. Capsules are involved in protection and adherence, not chemotaxis. Fimbriae help in attachment to surfaces, not in movement towards stimuli.

Correct Answer: C

Rationale: The correct answer is C: Transcription. Transcription is the process of synthesizing RNA from a DNA template. During transcription, RNA polymerase binds to the DNA and produces a complementary RNA strand. This process is essential for gene expression. Explanation for why other choices are incorrect: A: Transposition involves the movement of genetic elements within a genome, not the production of RNA from DNA. B: Translation is the process of synthesizing proteins from mRNA, not the production of RNA from DNA. D: RNA splicing is the process of removing introns and joining exons in pre-mRNA to produce mature mRNA, not the initial production of RNA from DNA.

Correct Answer: A

Rationale: The correct answer is A: Halogens. Chlorine belongs to the halogens group because it is a nonmetal element in group 17 of the periodic table. Halogens are highly reactive elements that have 7 electrons in their outer shell, making them eager to gain an electron to achieve stability. Chlorine specifically is a diatomic molecule with the chemical symbol Cl and atomic number 17. Option B: Heavy metals are elements with high atomic weights and densities, such as lead and mercury, which are not related to chlorine. Option C: Phenols are a class of organic compounds containing a hydroxyl group bonded to an aromatic ring, not related to chlorine. Option D: Alcohols are organic compounds characterized by the presence of a hydroxyl group (-OH), also not related to chlorine.