The pentose phosphate pathway (PPP) is a metabolic process that occurs in the cytoplasm of cells. It primarily serves two functions: generating NADPH, which is essential for biosynthetic reactions and antioxidant defense, and producing ribose-5-phosphate, a sugar necessary for the synthesis of nucleotides and nucleic acids. The pathway consists of two phases: the oxidative phase, where glucose-6-phosphate is converted into NADPH and ribulose-5-phosphate, and the non-oxidative phase, which interconverts various sugars. This pathway is crucial for cellular metabolism, especially in tissues that require high levels of NADPH, such as the liver and adipose tissue.