was present and performed exercise onitals) Nitrate Reduction Test OBSERVATIONS
ID: 165542 • Letter: W
Question
was present and performed exercise onitals) Nitrate Reduction Test OBSERVATIONS AND INTERPRETATIONS Using Table 5-7 as a guide, enter your results and interpretations in the chart below. Results Gas Color Alter After Organism Y N Reagents Zinc Interpretation Uninoculated Control to vonloaseous Nit (ote Change nitrogenous compound E Nos Noz nongpaseous vitros nous loubble to Start troo em Pae color NO N (ed don't. No nitrate reduction QUESTIONS 1 why is gas production not reco as Nitrate reduction when the organism is a known fermenter?Explanation / Answer
Answer:
1. Gas production is not recognized as nitrate reduction even when the organism is a known fermenter because organisms that can ferment can also produce gas. Therefore, even if gas is produced in the tube, it cannot be inferred whether its due to fermentation or by nitrate reduction.
2. The gas bubble produced in the Durham tube is nitrogen.
If the reagents & zinc do not produce any change, then the nitrates have been used up by the bacteria.
3. A bubble plus colour change would indicate the presence of some other kind of bacteria which is inconsistent with the test.
4. Semi-solid agar is thin enough to allow the cells to move to the level of medium that has the right concentration of oxygen for their optimal growth, and thick enough for them to stay there and grow enough that they can be detected easily.
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