Certified Pediatric Hematology Oncology Nurse (CPHON) Practice Exam

Glucose-6-phosphate dehydrogenase (G6PD) plays a critical role in the pentose phosphate pathway (PPP). This pathway is essential for cellular metabolism and is primarily involved in the production of NADPH, which is used in various biosynthetic reactions and in maintaining the redox balance of the cell. G6PD catalyzes the first step in the PPP, where glucose-6-phosphate is oxidized to 6-phosphogluconolactone, simultaneously reducing NADP+ to NADPH.

NADPH produced by the pentose phosphate pathway is crucial for biosynthetic processes, such as fatty acid synthesis and maintaining glutathione in its reduced form, which protects cells from oxidative damage. The pentose phosphate pathway also generates ribose-5-phosphate, which is vital for nucleotide synthesis.

The other pathways mentioned in the options have different roles. Glycolysis focuses on the breakdown of glucose to produce energy, the citric acid cycle is involved in energy production through the oxidation of acetyl-CoA, and the urea cycle is responsible for detoxifying ammonia in the liver. None of these pathways directly involve G6PD as a key regulatory enzyme, thus highlighting why the pentose phosphate pathway