Sedoheptulose 7-phosphate


The pentose phosphate pathway converts the six carbon sugar, glucose 6-phosphate, into the five carbon sugar, ribose 5-phosphate, an important component of many biomolecules including ATP, NAD, CoA, DNA and RNA. In addition to serving as the primary source of ribose, the pentose phosphate pathway also serves as the primary source of the cell's supply of NADPH. Differing structurally from NADH by the presence of a single phosphate, NADPH serves a different set of enzymes as coenzyme. NADH drives the electron transport system in energy metabolism, while NADPH is the primary source of reducing equivalents in biosynthesis.

WikiPremed Resources

Learning Goals


Be able to name the steps in the pentose phosphate pathway and describe the chemical changes occurring with each step.

Understand the metabolic role of the pentose phosphate pathway.

Possess a basic sense of the enzymatic mechanisms of ribulose 5-phosphate isomerase, pentose phosphate epimerase, transketolase, and transaldolase.

Be able to describe how the pentose phosphate pathway adjusts when cellular needs for NADPH and ribose 5-phosphate are not in balance, ie. when the need for one is much greater than the need for the other.

Suggested Assignments

The question server contains a general section covering basic concepts from gluconeogenesis, the pentose phosphate pathway, glyocogen metabolism, fatty acid metabolism, the urea cycle, and metabolic integration. After review complete the crossword puzzle for energy metabolism. Here is the solution to the puzzle.

Review the web resources for the pentose phosphate pathway.

Conceptual Vocabulary for The Pentose Phosphate Pathway