Final answer:
Fatty acids released from adipose tissue during fasting or energy demands attach to the protein albumin for transport through the bloodstream. Albumin's structural capacity to bind with hydrophobic molecules like fatty acids facilitates their solubility and delivery to tissues needing energy.
Step-by-step explanation:
During times of fasting or when there is a need for energy, fat stored in adipose tissues is broken down in a process known as lipolysis. The free fatty acids (FFA) released from triacylglycerols (TAG) in adipose tissue then need to travel through the bloodstream to reach tissues that will use them for energy.
However, since fatty acids are nonpolar and the bloodstream is an aqueous (water-based) environment, they are not freely soluble. To transport these fatty acids through the blood, they bind to serum albumin to form an FFA-albumin complex, increasing their solubility. Albumin is the major circulating protein in the bloodstream and has a significant role in the transport of a variety of biological molecules, including free fatty acids. Lipoproteins, classified by density, also play roles in lipid transport but are not the primary carriers of free fatty acids. When it comes to the transport of fatty acids in the blood after being released from the adipose tissue, albumin is the protein to which they primarily bind.