H2 is a product of some types of anaerobic metabolism and is produced by several microorganisms, usually via reactions catalyzed by iron- or nickel-containing enzymes called hydrogenases. These enzymes catalyze the reversible redox reaction between H2 and its component two protons and two electrons. Creation of hydrogen gas occurs in the transfer of reducing equivalents produced during pyruvate fermentation to water. The natural cycle of hydrogen production and consumption by organisms is called the hydrogen cycle. COUNT 3
QSN1 What enzymes are used to produce H2? ANS1 hydrogenases QSN2 When does hydrogen gas occur? ANS2 in the transfer of reducing equivalents produced during pyruvate fermentation to water QSN3 What is the natural cycle of hydrogen production and consumption by organisms called? ANS3 hydrogen cycle