What are the functions and compostitions of lipids, carbs, and proteins?

http://en.wikipedia.org/wiki/Nutrition

Lipids, carbohydrates, and proteins are three major macronutrients essential for human nutrition. Each of these nutrients serve different functions in the body and have different compositions.

Lipids: Lipids are a class of molecules that are insoluble in water but soluble in fat solvents. They are composed of carbon, hydrogen, and oxygen atoms. The main functions of lipids include energy storage, insulation, and protection of organs. Additionally, lipids are important in the formation of cell membranes and in the synthesis of certain hormones. Examples of lipids include triglycerides (fats and oils), phospholipids, and cholesterol.

Carbohydrates: Carbohydrates are molecules composed of carbon, hydrogen, and oxygen atoms. They can be classified into three types: monosaccharides (simple sugars), disaccharides (two monosaccharides bonded together), and polysaccharides (chains of monosaccharides). The primary function of carbohydrates is to provide energy to the body. Glucose, a monosaccharide, is the main source of energy for the brain. Carbohydrates also play a role in the structure of cells and as stored energy in the form of glycogen in the liver and muscles.

Proteins: Proteins are complex molecules composed of amino acids. They contain carbon, hydrogen, oxygen, and nitrogen, with some proteins also containing sulfur and phosphorus. Proteins have a wide variety of functions in the body. They are involved in growth and repair of tissues, enzyme reactions, transportation of molecules, immune system function, and as a source of energy (although carbohydrates and lipids are the body's preferred energy sources). Proteins are essential for the structure and function of cells and organs.

To explore further information on the functions and compositions of lipids, carbohydrates, and proteins, you can refer to the link provided: http://en.wikipedia.org/wiki/Nutrition