Which statement best explains how experimental results can distinguish the metabolic pathways used by Escherichia coli and Staphylococcus epidermidis?

• A. Experimental results cannot provide any information about the metabolic pathways of these bacteria.
• B. E. coli and S. epidermidis both produce ethanol as the main fermentation product, making them indistinguishable by metabolic assays.
• C. Both E. coli and S. epidermidis exclusively use aerobic respiration, so their metabolic end products are identical.
• D. E. coli typically utilizes mixed-acid fermentation, while S. epidermidis primarily uses lactic acid fermentation, leading to different end products detectable in experiments.

Answer: (D)

Verified step by step guidance

1. Understand the metabolic pathways commonly used by Escherichia coli and Staphylococcus epidermidis: E. coli typically performs mixed-acid fermentation, producing a variety of acids such as lactic acid, acetic acid, and formic acid, while S. epidermidis primarily carries out lactic acid fermentation, producing mainly lactic acid.
2. Recognize that different fermentation pathways result in distinct metabolic end products, which can be detected and measured experimentally using biochemical assays or pH indicators.
3. Design experiments to detect and differentiate these end products, such as using specific media that change color in response to acid production or employing chromatography techniques to identify the types of acids produced.
4. Analyze the experimental results by comparing the detected fermentation products: the presence of multiple acids suggests mixed-acid fermentation (E. coli), whereas predominantly lactic acid indicates lactic acid fermentation (S. epidermidis).
5. Conclude that the differences in metabolic end products allow experimental results to distinguish between the metabolic pathways used by E. coli and S. epidermidis.