2. Chemistry of Life Nature of Matter

3. Matter- Anything that has Mass and Volume Atoms are the smallest unit of matter that cannot be broken down by chemical means Atoms consist of protons, electrons, and neutrons (symbols, atomic #, atomic mass) Elements are pure substances that are made of only one kind of atom. A chunk of gold is made up of only gold atoms Isotopes- atoms that have different number of neutrons (ie. Carbon 14)

4. Chemical Bonding Bonding is a force that joins atoms together Compounds are substances that consist of 2 or more elements joined together 3 types of chemical bonds (covalent, hydrogen, & ionic)

5. Bonding Covalent bonds form when 2 or more atoms share electrons Hydrogen bonds form when there is a weak chemical attraction between polar bodies Polar bodies-unequal distribution of electrical charges Ionic bonds form when an atom or molecule gains or loses electrons

6. Water in Living Things Water is the medium in which most cellular events take place Water can store heat Water is used to cool body (sweat) Water helps maintain homeostasis

7. Cohesion/Adhesion Cohesion is an attraction between substances of the same kind (water drops on penny) Adhesion is the attraction between different substances (think adhesive tape) Adhesion powers capillary action in plants

8. Solutions A solution is a mixture in which one or more substances are evenly distributed in another substance Solvent -water Solute - salt Solubility - the amount of solute that dissolves in solvent

9. Acidity - pH Acids- compounds that form hydrogen ions (H+) when dissolved in water Bases- compounds that form hydroxide (OH-) ions when dissolved in water 0 - 6.9 = acid 7.1 - 14 = base 7 = neutral

10. Chemistry of Cells Organic compounds contain carbon atoms 4 classes of organic compounds that are found in living things are: carbohydrates, lipids, proteins, and nucleic acids

11. Carbohydrates Consist of carbon, hydrogen and oxygen (1-2-1 ratio) Key source of energy and are found in most foods (grains, fruits) Simple sugars make up carbohydrates Mono, di, polysaccharides

12. Lipids Nonpolar molecules that are not soluble in water Fats, phospholipids, steroids, and waxes Lipids are an important part of the cell membrane Fats are lipids that store a lot of energy Fats consist of 3 fatty acids bonded to glycerol

13. Proteins Large molecules formed by amino acids 20 different a.a. Enzymes are made of amino acids-help with chemical reactions Examples of proteins: –Collagen, antibodies, hemoglobin

14. Nucleic Acids Nucleic acids are found in cells - genes Nucleic acids are made of nucleotides (sugar, base, and phosphate group) 2 types of nucleic acids - DNA & RNA ATP - single nucleotide with 2 extra storing phosphate groups (energy released in respiration)

15. Energy and Chemical Reactions Energy can be stored or released by chemical reactions Chemical bonds b/w atoms are broken and new ones are formed Reactants- starting materials Products- ending materials Energy can either be released or absorbed during chemical reactions (page 39) Endo vs. exothermic Activation energy is the energy needed to start a chemical reaction

16. Enzymes Enzymes increase the speed of chemical reactions (most are proteins) Enzymes are catalyst, which are substances that reduce the activation energy Enzymes help maintain homeostasis by increasing chemical reaction speed Enzymes act only on specific substrates (specific shape determines activity) page 41 The rate in which enzymes work can be influenced by temperature and pH.