Question

Fatty acid synthesis and β-oxidation do not occur simultaneously in a cell. Explain why preventing simultaneous synthesis and oxidation is necessary and how its achieved. In your answer, be sure to describe the specific regulatory mechanisms involved. In your answer, you must also compare and contrast the pathways (include locations, enzymes, starting products and ending products).

Answer 1

Fatty acid synthesis ues Acetyl coA to build long chain FA (LCFA). And the fatty acid synthesis mostly take place in liver and lactating mammary glands and to a lesser degree in adipose tissue.

Free Fat ------> AcylCoA Thioester, which has high energy bond

ATP is required in this synthesis. This step is fully reversible, as ATP and the Actyl-CoA The ester product both have equivalent energy levels. And to prevent the reversibility, the reaction is coupled to Pyrophosphatase , which catalyzes Pyrophosphat------.2Inorganic Phosphate, which breaks a high energy bond to drive the reaction to right.

And beta oxidation is actually a four step. In oxidation process the Acyl-CoA Dehydrogenase catalyzes an elimination of hydrogens on the alpha- carbon to create the Alpha, Beta- unsaturated Acyl-CoA.

FAD------> FADH₂ is the correspondance reduction.

And in the Hydration process in which a creation of the OH group on the beta-carbon. double bond  the process and in this the chemistry mainly occur on the beta-Carbon per turn of the cycle. Further, in the oxidation process the oxidation of the OH group to a carbonyl function. NAD⁺-----> NADH is the coressponding reduction.

Hence, fatty acid synthesis and beta oxidation do not occur simultaneously in a cell. Preventing simultaneous synthesis and oxidation is necessary as the newly synthesis fats are not immediately broken down again. And prevent the transport of fats and thereby effectively slowing the beta oxidation.