Ribulose-5-phosphate is a five-carbon sugar phosphate that plays a crucial role in the pentose phosphate pathway, a metabolic pathway parallel to glycolysis. It is formed from ribulose bisphosphate through the action of the enzyme ribulose bisphosphate carboxylase/oxygenase (RuBisCO) and is important for the synthesis of nucleotides and nucleic acids. In the pentose phosphate pathway, ribulose-5-phosphate can be converted into other sugars, such as ribose-5-phosphate and xylulose-5-phosphate. These sugars are essential for various biosynthetic processes, including the production of ATP and NADPH, which are vital for cellular energy and metabolism.