Final answer:
The statement that AMPK stimulates TAG synthesis is false. AMPK phosphorylates and inactivates key enzymes in fatty acid synthesis, reducing TAG production and conserving energy within the cell.
Step-by-step explanation:
The statement AMPK stimulates TAG synthesis is false. Adenosine monophosphate-activated protein kinase (AMPK) is an enzyme that plays a crucial role in energy balance and metabolic stress. AMPK serves as an energy sensor within the cell, and when activated by low energy states, it acts to restore energy balance by stimulating catabolic pathways that generate ATP, and by inhibiting anabolic pathways, such as those involved in triacylglycerol (TAG) synthesis, that consume ATP. In terms of fatty acid metabolism, AMPK phosphorylates and inactivates acetyl-CoA carboxylase (ACC), which is a pivotal enzyme in the biosynthesis of fatty acids.
Inhibition of ACC decreases malonyl-CoA levels, which in turn diminishes fatty acid synthesis and may facilitate fatty acid oxidation since malonyl-CoA inhibits carnitine palmitoyltransferase 1 (CPT1), a key regulator of fatty acid oxidation. Therefore, the activation of AMPK does not stimulate TAG synthesis; it actually inhibits it to conserve energy.