One function of both alcohol fermentation and lactic acid fermentation is to a. oxidize nadh to nad+. b. reduce nad+ to nadh. c. reduce fad+ to fadh2. d. reduce fadh2 to fad+. e. none of the above

a. oxidize NADH to NAD+

Explanation:

Alcohol fermentation and lactic acid fermentation share a common step that is glycolysis. Since the organisms or cells that carry out the fermentation lack oxygen, oxidative phosphorylation can not oxidize NADH into NAD+. Without the supply of NAD+, glycolysis cannot occur as NAD+ serves as electron acceptor during redox reactions of glycolysis.  

To maintain the continuity of glycolysis, alcohol fermentation and lactic acid fermentation oxidize the NADH into NAD+ which in turn enter the glycolysis.  

condensation. good luck!

enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products