II. Data analysis: You are working in a metabolic lab and are studying 2 differe
ID: 94547 • Letter: I
Question
II. Data analysis: You are working in a metabolic lab and are studying 2 different mutant strains of E. coli. These mutant strains are conditional mutants. When grown at low temperature, they appear phenotypically normal. However, when grown at elevated temperatures, they grow much more slowly and you find that they lack certain compounds found in the Embden Myerhof pathway. The data you gather is shown in the table below. (+ = normal, - = decreased levels, ++ = increased levels). Please answer each question using complete sentences to describe your answer and the reasoning behind each answer. (2.5 pts) Mutant Strain #EC14 Mutant Strain #EC17 Glucose-6-phosphate ++ ++ Fructose-6-phosphate ++ ++ Fructose-1,6,bisphosphate ++ - Glyceraldehyde-3-phosphate ++ - 1,3-bisphosphoglycerate ++ - Phosphoenolpyruvate ++ - Pyruvate - - 1. Which enzyme is missing from EC14? Which enzyme is missing from EC17? Explain how you determined this? 2. If you wanted to test bacteria for their ability to complete glycolysis, what compound would you try to detect? Why? 3. Would you expect to see pyruvate being produced after the addition of glyceraldehyde-3-phosphate to Mutant Strain EC14? If you added it to EC17, would pyruvate be produced? Indicate yes or no and explain why you answered the way you did. 4. If the electrons released in the earlier steps of glycolysis are added to pyruvate to form lactic acid, what process has occurred? Is pyruvate the electron donor or acceptor in this exchange? Has it been reduced or oxidized to form lactic acid?
Explanation / Answer
1) The enzyme enolase is missing from EC14 mutant strain because pyruvate is not found and all other metabolic intermediates are found in high concentration.
The enzyme phosphofructokinase is missing in EC17 mutant strain.This is because phosphofructokinase catalyses the conversion of fructose 6-phosphate to fructose-1,6, bisphosphate. Fructose-1,6-bisphosphate and subsequent glycolytic intermediates are not produced by the strain EC17 and therefore this enzyme is absent in this mutant strain.