Summary
Produces NADPH and ribose sugars for biosynthesis and antioxidant defence.
In depth
The oxidative phase makes NADPH and ribulose-5-phosphate; the non-oxidative phase interconverts sugars. Active in liver, adipose tissue, adrenal cortex and red blood cells. G6PD deficiency causes haemolytic anaemia, protecting against malaria.
It provides ribose for nucleotides and NADPH for biosynthesis and glutathione recycling. Inhibition of G6PD affects red cell protection.
Common mistake: the pathway doesn't produce ATP directly.
The pentose phosphate pathway (PPP), also called the hexose monophosphate shunt, runs in the cytoplasm alongside glycolysis. Its oxidative phase converts glucose-6-phosphate to ribulose-5-phosphate and makes two NADPH; the non-oxidative phase interconverts sugars of 3 to 7 carbons.
NADPH provides reducing power for fatty acid and cholesterol synthesis and keeps glutathione reduced, protecting against oxidative damage, especially in red blood cells. Ribose-5-phosphate is needed for nucleotides and DNA. Activity is high in liver, adipose tissue, adrenal glands and dividing cells.
Example: glucose-6-phosphate dehydrogenase (G6PD) deficiency causes haemolysis after fava beans or certain drugs, although it also confers some protection against malaria.
Frequently asked questions
What is Pentose Phosphate Pathway?
Produces NADPH and ribose sugars for biosynthesis and antioxidant defence.
Which area of biology covers Pentose Phosphate Pathway, and how advanced is it?
Pentose Phosphate Pathway is one of the 53 topics in Metabolism & Bioenergetics. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Reactive Oxygen Species, Gluconeogenesis, Glycolysis.
Why does Pentose Phosphate Pathway matter?
It makes no ATP but serves biosynthesis and defence.
Can you give an example of Pentose Phosphate Pathway?
Fava beans trigger haemolysis in G6PD-deficient people.
What should I learn before Pentose Phosphate Pathway?
Work through the Beginner topics in Metabolism & Bioenergetics first, such as Metabolism, Anabolism and Catabolism, ATP, then return to Pentose Phosphate Pathway. Intermediate topics assume the Beginner vocabulary.
What topics are related to Pentose Phosphate Pathway?
The closest topics to Pentose Phosphate Pathway are Reactive Oxygen Species, Gluconeogenesis, Glycolysis, Brown Fat Thermogenesis. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Pentose Phosphate Pathway?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Pentose Phosphate Pathway. To practise the whole of Metabolism & Bioenergetics, use the Metabolism & Bioenergetics quiz.
How is Pentose Phosphate Pathway different from Reactive Oxygen Species?
Pentose Phosphate Pathway: Produces NADPH and ribose sugars for biosynthesis and antioxidant defence. Reactive Oxygen Species: Electron leakage produces superoxide and other oxidants that cause damage but also act as signals. Read both side by side and note what each one explains.
What is a common mistake about Pentose Phosphate Pathway?
The pathway doesn't produce ATP directly.
How should I study Pentose Phosphate Pathway step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Reactive Oxygen Species and explain the difference aloud. Finally, take the Metabolism & Bioenergetics quiz and come back to this page for any question you miss.