Which Organic Molecules Are Mostly Related to Lipids?

Steroids

• Chemically, steroids are chains of carbon rings that share common elements. Physiologically, they are organic molecules that go through cell walls and attach to the nucleus walls. They including building blocks like cholesterol and are the basis of many hormones  --- the message molecules that the brain uses to control the functioning of cells. The subgroup called sterols refer to steroids that contain an alcohol functional group. The -ol ending usually indicates an alcohol group on an organic molecule.

Fatty Acids

• Fatty acids are long chains of carbon-hydrogen (CH) structures which end in a carboxyl (COOH) group. Fatty acids are hydrophobic (water hating) on one end and hydrophilic (water loving) on the other end and so automatically arrange themselves back to back into semipermeable sheets when placed in an aqueous solution. They make up the walls of cells, liposomes and vesicles. Fatty acids form the building blocks for more complex lipids, such as phospholipids and glycolipids. Glycolipids are an important structural component of neurons and other neural tissue. When fatty acids are not used for construction they can be used for fuel in skeletal and heart muscles.

Wax

• All lipids are hydrophobic --- they do not like water, and water molecules will not attach to most lipids. That is the one thing they all have in common. Waxes are especially water repellent. Waxes coat the surface of seeds, leaves, feathers and skin. Waxes also form a protective barrier at all body openings on mammals. Chemically, waxes are esters of fatty acids, usually formed when an acid reacts with an alcohol. Nature uses waxes to repel water, prevent dehydration and protect living organisms from small predators, especially microbes.

Fats and Oils

• Fats and oils are esters of fatty acids with glycerol. Fats are used to store energy in animals, and oils are used to store energy in plants. The group is collectively called triglycerides. Triglycerides are called oils if they are liquid at room temperature --- these are usually from plants, but some fish triglycerides are oils. Triglycerides are called fats when they are solids at room temperature. Saturated fats are made from saturated fatty acids --- those that have no double bonds between the carbon atoms. It is the unsaturated fats --- those with double carbon bonds -- that are good for you.