Your immune system can recognize these markers. This is the chemical basis of why you cannot receive an organ transplant from just any person. All fats are lipids but not all lipids are fats. Lipids can be divided into a few groups. You most commonly think of them as fats.
Fats can be oils like olive oil and corn oil as well as solids like grease, lard and butter.
A second group of lipids are hormones. Cholesterol is a very famous lipid, it can be altered into estrogen and testosterone within your cells. A fat is one type of a lipid. There are four different types of nucleotides in DNA, they are symbolized by the letters A, T, C and G. All the DNA in your body is made of these four building blocks. The sequence of the As, Ts, Cs, and Gs in each of your cells is exactly the same and there is nobody else in this world with exactly the same sequence as you.