1. Protons ­ positive charge, Neutrons ­ no charge, Electrons ­ negative charge. 2. Valence electrons ­ the electrons in the outermost energy level of an atom. They determine how an atom will react in a chemical reaction. 3. A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms. An ionic bond is the bonding between a nonmetal and a metal, that occurs when charged atoms attract after one loses one or more of its electrons,and gives it to the other molecule. 4. Carbon. 5. Carbs, lipids, proteins, and nucleic acids. 6. Nutrients. Water, proteins, lipids, carbs, minerals, and vitamins. 7. Carbon, Hydrogen, and Oxygen. The three types are monosaccharides, disaccharides, and polysaccharides. 8. The three most common types of polysaccharides are starch, glycogen, and cellulose. Starch is a glucose polymer and insoluble in water; they must be digested with amylases. Glycogen is the storage form of glucose in animals, where starch is the same in plants. Cellulose forms most structural components in plants, and is indigestible by humans. 9. Carbon, Hydrogen, Oxygen, and sometimes Phosphorus. Lipids ­ a class of organic compounds that are fatty acids or their derivatives and are insoluble in water but soluble in organic solvents. They include many natural oils, waxes, and steroids. 10. Lipids provide energy, and are needed to produce hormones. You wouldn't be able to digest and absorb food properly without lipids. 11. Fatty Acids ­ a carboxylic acid consisting of a hydrocarbon chain and a terminal carboxyl group, especially any of those occurring as esters in fats and oils. Triglycerides ­ an ester formed from glycerol and three fatty acid groups. Phospholipids ­ a lipid containing a phosphate group in its molecule.

Steroids ­ a large class of organic