In humans, glucose is metabolised by glycolysis and the pentose phosphate pathway. In biochemistry, a ribonucleotide is a nucleotide containing ribose as its pentose component. The protein functions by blocking glycolysis and directing the pathway into the pentose phosphate shunt. GDP consists of a pyrophosphate group, a pentose sugar ribose, and the nucleobase guanine. Ribose 5-phosphate (R5P) is both a product and an intermediate of the pentose phosphate pathway. Like the pentose phosphate pathway, these pathways are related to parts of glycolysis. Ribulose sugars are composed in the pentose phosphate pathway. The accumulation of G6P will shunt carbons into the pentose phosphate pathway. The intraradical hexose enters the oxidative pentose phosphate pathway, which produces pentose for nucleic acids. The pentose phosphate pathway is an alternative method of oxidizing glucose. This occurs via the pentose phosphate pathway. The remaining fraction of glucose is shunted primarily down the pentose phosphate pathway. Ribulose and xylulose occur in the pentose phosphate pathway. R5P is produced in the pentose phosphate pathway in all organisms.