In humans/animals, the main cells that store fat for energy are adipocytes. These fat cells are found under the skin, in the abdominal cavity and surround major organs. The fatty tissue is the body’s main means of storing energy for long periods of time. Lipids, like triglycerides are stored in the adipocytes until ready to be used by the body for energy. Fat is broken down through metabolism in the mitochondria of the cell. The triglycerides are broken down into glycerol and 3 fatty acids. The glycerol can be easily converted to glyceraldehyde 3 phosphate, an intermediate of glycolysis. From there it can go through the Krebs Cycle and electron transport chain to make ATP. The 3 fatty acids can be broken down into 2 carbon subunits that are converted to Acetyl CoA which goes directly into the Krebs cycle and then electron transport chain to make more ATP. Fats are actually ...view middle of the document...
Unsaturated fats are usually liquid at room temperature but can also be found in avocados, fish, nuts, etc… The diagram below shows the kink in the chain of the unsaturated fat molecule caused by the double bond. It is at this point that the hydrogens are unable to bond to all the carbons.
Fatty acids perform many functions in the body. Fatty acids are the principal storage form of energy for most organisms. They are also the building blocks for phospholipids (part of the cell membranes). They act as a targeting molecule – directing proteins to their correct place on the membrane.
Every cell membrane incorporates a fluid mosaic model. The “mosaic” of protein molecules embedded in a lipid bilayer. It’s fluid as most proteins and lipid molecules drift through it. The membrane consists of a phospholipid bilayer embedded with various proteins. The proteins help to get polar/hydrophilic molecules through the plasma membrane. Polar molecules have difficulty passing thru the hydrophilic membrane. Nonpolar molecules however, easily pass thru. The proteins can be integral proteins, meaning they go all the way through the lipid bilayer or peripheral proteins that sit on the hydrophilic outer layer and wait for something to happen. The layers are somewhat fluid, allowing the proteins to move across them. See diagram below.
No fat diets can actually do more harm than good. The body needs moderation of all energy producing macronutrients; fats, carbohydrates and proteins. By not eating any fat, the body starts to utilize the fats stored in the body, thus depleting the stores and people lose weight. However, once those stores are gone, the good fats or HDL’s, are no longer able to filter out the bad cholesterol. This can lead to increased cholesterol levels in the blood and heart disease. A no fat diet also causes poor vitamin absorption of the necessary fat soluble vitamins A, D, E and K. Fats transport those vitamins from the liver to various parts of the body.
Sanders, J. (2013). Fatty Acid Structure video.
Wolfe, George. Thinkwell Biochemistry, Thinkwell Biology lectures.