i think I have the right answers I\'m just not sure single-celled microorgaag .

Question

i think I have the right answers I'm just not sure

single-celled microorgaag . The sample has been sitting without agitation for two days in the lab, so when you measure O2 levels in the water they are very low. You add glucose to the sample and measure increased levels of lactic acid after 2 hours. Based on these data, which of the following statements are true? A. There are predominantly lactic acid fermenting prokaryotes in the sample. B. Only prokaryotes capable of respiration are in the sample. There are predominantly mixed acid fermenting prokaryotes in the sample. The organisms in the sample are using glycolysis. The organisms in the sample are using -oxidation. E. Ammonium nitrate (NH4N03) is a common nitrogen fertilizer, and might be used in landscaping around the pond. You add this to the sample in Question 1 and observe the lactic acid is rapidly consumed, and CO, and N2 are produced. Based on these data, which of the of following statements are true? A. Some organisms are capable of respiration. B. The Co2 produced is likely a byproduct of organisms using the citric acid cycle. C. Some of the prokaryotes can use ammonia (NH) as a terminal electron acceptor D. Some of the prokaryotes can use nitrate (NO3) as a terminal electron acceptor. Some of the prokaryotes can convert nitrate (NO3) to N2 and O2, and are using O2 as their terminal electron acceptor.

Explanation / Answer

Question 1.

Answer. (C)

Explaination : Mixed acid fermentations occur when bacteria utilize two or more different pathways in the terminal steps of fermentation. This pathway is utilized by "Facultative anaerobes" like  E. coli and Enterobacter aerogenes. They perform aerobic respiration in the presence of O2, anaerobic respiration if there are suitable alternative electron acceptors such as nitrate, fumarate is present. In the absence of any such acceptor then these bacteria will ferment glucose to a mixture of lactate, formate, acetate and succinate acids plus ethanol.

Question 2.

Answer. (D) : already explained in the above answer.

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