1.The nucleus and the electron cloud (electrons, neutrons, protons); protons and neutrons in the nucleus, and electrons in the electron cloud.

2. The atomic mass number is the sum of the protons and neutrons in the nucleus, where as atomic number is just the number of protons.

3. An atom of an element with a different mass number than another atom of that same element. Carbon-12.01 in an isotope the mass could be 16.

4. Ionic bonds form b/w ions. These bonds involve cations and anions. And when in solution they are considered electrolytes. Usually b/w a metal(Na) and a nonmetal(Cl) which forms sodium chloride.; Covalent bonds form when atoms share electrons such as NH3. Can be single and double, such as CO2, and can be polar and nonpolar, which have a uniform electrical charge.; Hydrogen bonds are they STRONGEST intermolecular force. They form b/w H w/ coumpounds of F,O and N, such as OH. They are b/w water molecules and cause surface tension, and influence the shape of larger molecules. They form some type of compound.

5. Because any disruption in the balance can cause problems, and pH helps to maintain homeostasis.

6. Carbohydrates- carbon/hydrogen/oxygen; in a ratio of 1:2:1- Monosaccharides, Disaccharides and Polysaccharides- which include cellulose, starches and glycogen.

7.Lipids-primarily fats, oils and waxes- Fatty acids, eicosanoids, glycerides, steroids and phospholids& glycolipids.

8.Proteins- made of carbon, hydrogen, oxygen and nitrogen. are the most abundant and important class of molecules. 7 functions: support, movement, transport, buffering, metabolic regualtion, coordination and control, and defense.- antibodies.

9.Nucleic Acids- made of carbon, hydrogen,oxygen, nitrogen, and phosphorus. store and process information- DNA & RNA- chains of nucleotides(A,G,C,T(DNA) and U(RNA)).

10. primary structure: the order of amino acids;secondary structure: hydrogen bonds form;tertiary structure: folds the secondary structure; quaternary structure: several tertiary structures together.

11.It is an adenine base with a sugar and three phosphate groups attached to