Figure 2.21 The glycolytic pathway. OPP, Oxidative pentose phosphate pathway; PPi, pyrophosphate, Pi, inorganic phosphate; TPI, triose phosphate isomerase; NAD⁺, nicotinamide adenine dinucleotide (oxidised); NADH, nicotinamide adenine dinucleotide (reduced); NADP⁺, nicotinamide adenine dinucleotide phosphate (oxidised); NADPH; nicotinamide adenine dinucleotide phosphate (reduced); ATP, adenosine triphosphate; ADP, adenosine diphosphate;  MDH, malate dehydrogenase; PEPC, phosphoenolpyruvate carboxylase; PK, pyruvate kinase. (Original drawing courtesy Nicolas Taylor & Harvey Millar)