Storage molecules

Fat is the major way we store energy. Fat is stored principally in adipose tissue and can be stored in virtually unlimited amounts. Fat is metabolized through p oxidation to acetyl-CoA and then through the TCA cycle, where it s burned completely to CO2 to make ATP. Fat cannot be used to make carbohydrate because acetyl-CoA cannot be converted directly to precursors of glucose without losing its carbon atoms first (you ll see what this really means later). 

---

There are only three types of storage molecules glycogen, fat, and protein. These three storage forms are all connected, and that s what energy metabolism is all about—the connections. When metabolism works normally, we re assured of a relatively constant supply of energy and glucose. 

Biologically, carbohydrates are most important as energy sources. This is especially true for monosaccharides, disaccharides, and starches. Starches also function as energy storage molecules in plants. Cellulose is an essential component of plant cell walls. 

The higher energy yield per carbon atom from fatty acid compared with carbohydrate reflects its higher level of reduction, which consequently allows more oxidation. Thus, fat is logically the preferred storage molecule to carbohydrate. This is... 

---