The most impoant source of reducing equivalents for fatty acid synthesis in the liver is
The oxidative reactions of the pentose phosphate pathway(HMP pathway) are the chief source of the hydrogen required for the reductive synthesis of fatty acids. NADPH is involved as a donor of reducing equivalents.Glycolysis is the metabolic pathway that conves glucose C6H12O6, into pyruvate, CH3COCOO- + H+. The free energy released in this process is used to form the high-energy molecules ATP (adenosine triphosphate) and NADH (reduced nicotinamide adenine dinucleotide)The citric acid cycle is the final pathway for the oxidation of carbohydrate, lipid, and protein. Their common end metabolite, acetyl-CoA, reacts with oxaloacetate to form citrate. By a series of dehydrogenations and decarboxylations, citrate is degraded, reducing coenzymes, releasing two CO2, and regenerating oxaloacetate.The reduced coenzymes are oxidized by the respiratory chain linked to the formation of ATP. Thus, the cycle is the major pathway for the formation of ATP and is located in the matrix of mitochondria adjacent to the enzymes of the respiratory chain and oxidative phosphorylation. The uronic acid pathway is an alternative pathway for the oxidation of glucose that does not provide a means of producing ATP but is utilized for the generation of the activated form of glucuronate, UDP-glucuronate which is mainly used for detoxification of foreign chemicals and for the synthesis of Mucopolysaccharides. The utilized glucuronate produced in this pathway is conveed to xylulose 5-p which is fuher metabolized through HMP pathway.The pentose phosphate pathway (also called the phosphogluconate pathway and the hexose monophosphate shunt) is a metabolic pathway parallel to glycolysis. It generates NADPH and pentoses (5-carbon sugars) as well as ribose 5-phosphate, the last one a precursor for the synthesis of nucleotides. While it does involve oxidation of glucose, its primary role is anabolic rather than catabolic.There are two distinct phases in the pathway. The first is the oxidative phase, in which NADPH is generated, and the second is the non-oxidative synthesis of 5-carbon sugars. For most organisms, the pentose phosphate pathway takes place in the cytosolRef: Harpers biochemistry 30th edition; page no-234
Glycolysis
TCA cycle
Uronic acid pathway
HMP pathway
Metabolism of lipid