Fatty acid
Malonyl-CoA is then involved in a repeating series of reactions that lengthens the growing fatty acid chain by two carbons at a time. Almost all natural fatty acids, therefore, have even numbers of carbon atoms. When synthesis is complete the free fatty acids are nearly always combined with glycerol (three fatty acids to one glycerol molecule) to form triglycerides, the main storage form of fatty acids, and thus of energy in animals. However, fatty acids are also important components of the phospholipids that form the phospholipid bilayers out of which all the membranes of the cell are constructed (the cell wall, and the membranes that enclose all the organelles within the cells, such as the nucleus, the mitochondria, endoplasmic reticulum, and the Golgi apparatus).
Cat food
A fat is a type of lipid which comes in the form of many different molecules throughout the body, and fatty acids are just one type of fat that can be found. 
Fatty acids come in a variety of molecular shapes, sizes and chemical compositions. They can also be divided into many different categories. Fatty acids can become attached to different molecules like carbohydrates or proteins and can elicit a wide range of functions in the body. Some of those functions include: providing long-term energy storage, insulation (prevents heat loss, protects vital organs, helps transmit nerve impulses faster), structure, transportation around the body for nutrients and other biological molecules, and can also be precursors to other compounds in the body such as hormones (some of which are important for gut/immune/overall health). The length, degree of saturation and configuration of a fatty acid affects how it is broken down, absorbed and utilized in the gastrointestinal tract (GIT).