1. Lipids

2. The lipids are organic molecules, present in nature; are insoluble in water (hydrophobic), while they are soluble in organic solvents non-polar, such as diethyl ether or acetone. From the structural point of view, are mainly consisting of carbon and hydrogen atoms joined together by covalent bonds almost polar and arranged symmetrically. What are lipids?

3. Many important functions in the human body - Energy intake - Provide essential fatty acids to the body - Promote the intestinal absorption of fat- soluble vitamins - Are the fundamental components of cell membranes in all tissues - Some of the lipids are precursors of compounds that have important regulatory functions in the body. - Influence blood lipid

4. Kinds of lipids Triglycerides Phospholipids Steroids Waxes

5. Triglycerides A triglyceride is formed by the union of a molecule of glycerol with three fatty acids, which differ according to their length and the presence or absence of double bonds. The triglycerides have an important role in metabolism as energy sources.

6. Phospholipids The phospholipid is a lipid with a polar head water-soluble of phosphate and a tail apolar non-water soluble. The phospholipids are the constituents of the plasma membranes of cells, in the form of double layer. They are also involved in intercellular signaling

7. Steroids Steroids are characterized by a structure carbonaceous to four fused rings. The most important steroid is cholesterol through which are synthesized all the sex hormones. A group of hormones, produced by the adrenal glands, is a part of this family. All steroids have the same structure; they are distinguished only by the presence of various functional groups along the rings.

8. Waxes Waxes are esters of fatty acids with a high number of carbon atoms. These can be saturated or unsaturated, straight chain and branched chain. Waxes are constituents of living things, plant and animal world. They form the protective layer of plants, the skeleton of many insects and the lining of the water feathers.

9. di Francesca Donateo Annapaola Donateo