1. Hexose Monophosphate

2. Hexose Monophosphate Pentose Phosphate Pathway
Glycolysis, TCA, and oxidative phosphorylation are primarily concerned with the generation of ATP.
The PPP meets the need of all organisms for a source of NADPH to use in reductive biosynthesis.
The reducing power is NADPH.
There is a fundamental distinction
NADH 
NADPH 
The direction of HMP depends on the supply and demand for intermediates in the cycle…

4. Two Major Functions NADPH Ribose Overall reaction:
3G-6-P + 6NADP+  3CO2 + 2G-6-P + Glyceraldehyde-3P + 6NADPH + 6H+
It occurs in the cytosol because NADP+ is used as a hydrogen acceptor.
There are two sequential reactions.
Oxidative
Nonoxidative

9. Oxidative and Nonoxidative Reactions
In oxidative, G-6-P undergoes dehydrogenation and decarboxylation to give a pentose ribulose-5-P.
In nonoxidative, ribulose 5-P is converted back to G-6-P by a series of reactions involving two enzymes
Transketolase
Transaldolase
Dehydrogenation of G-6-P is the major biological control of the HMP.
G-6-PD is strongly inhibited by NADPH.

10. Oxidative Branch