Microbes are often identified using biochemical tests that detect specific enzymes of metabolic pathways. e. coli typically ferments lactose, whereas the dysenterybacterium, shigella, does not. if a pure culture of each bacterium were placed in a tube containing lactose as the only food source, and a chemical indicator changed color if the tube became acid, what would the tubes look like after the bacteria were incubated?
a. both tubes would show the evidence of lactose fermentation by turning acidic and changing the ph indicator. b. both tubes would show the evidence of lactose fermentation by turning alkaline. c. neither tube will show any change. d. the tube with e. coli would indicate a ph change, and the shigella tube would indicate no change.