Respiration, primary metabolic pathway

The principal anabolic pathways for secondary metabolites originate from just a few intermediates of primary metabolic pathways, such as acetyl CoA, shikimic acid, and melvonic acid.86 Among the important cofactors are ATP, NADPH, and S-adenosylmethionine, which need to be continuously regenerated via primary metabolic pathways of respiration or photosynthesis. The fact that secondary metabolism shares chemical precursors with primary metabolism means that secondary and primary metabolic pathways may compete for substrates and cofactors, strongly suggesting that trade-offs occur at the biochemical level. 

Plant cells produce far more chemical compounds than is necessary for their basic functions i.e., biochemical pathways for survival and propagation. Basic or primary metabolism refers to all biochemical processes for the normal anabolic and catabolic pathways, which result in assimilation, respiration, transport, and differentiation. Basic or primary metabolism is shared by all cells, while secondary metabolism generates diverse and seemingly less essential or nonessential byproducts called secondary products. The secondary products are the colors, flavors, and smells, which are the sources of fine chemicals such as drugs, insecticides, dyes, flavors, and fragrances, and plant-growth regulators found in medicinal plants. 

Although the mitochondria are the primary site of oxidation for dietary and storage fats, the peroxisomal oxidation pathway is responsible for the oxidation of very long-chain fatty acids, jS-methyl branched fatty acids, and bile acid precursors. The peroxisomal pathway also plays a role in the oxidation of dicarboxylic acids. In addition, it plays a role in isoprenoid biosynthesis and amino acid metabolism. Peroxisomes are also involved in bile acid biosynthesis, a part of plasmalogen synthesis and glyoxylate transamination. Furthermore, the literature indicates that peroxisomes participate in cholesterol biosynthesis, hydrogen peroxide-based cellular respiration, purine, fatty acid, long-chain... 

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