Read each question carefully. Write your response in the spaceprovided for each part of each question. Answers must be writtenout in paragraph form. Outlines, bulleted lists, or diagrams aloneare not acceptable and will not be scored.

Enolase is an enzyme that catalyzes one reaction in glycolysisin all organisms that carry out this process. The amino acidsequence of enolase is similar but not identical in the organisms.Researchers purified enolase from  Saccharomycescerevisiae, a single-celled eukaryotic yeast that grows bestat  37°C, andfrom  Chloroflexus  aurantiacus, a bacteriumthat grows best at the much higher temperature of  55°C.The researchers compared the activity of purified enolase from thetwo organisms by measuring the rate of the reaction in the presenceof varying concentrations of substrate and a constant amount ofeach enzyme at both  37°C and  55°C.

(a) Depending on the organism, the optimal  pH forenolase to catalyze its reaction is between  6.5and  8.0.  Describe how a  pH belowor above this range is likely to affect enolase and its catalyticability.

(b)  Identify the appropriate negative control theresearchers most likely used when measuring the reaction rate inthe presence of each organism’s enolase.

(c) The researchers predict that for any particularconcentration of substrate, the  C. aurantiacusenolase-catalyzed reaction is more rapid at  55°C thanat  37°C. Provide reasoning to  justify theresearchers’ prediction.