1. Chapter 2

2.  Matter – anything that occupies space and has mass  Molecules – particles of matter made up of atoms  Atoms – protons, neutrons, electrons

4. Atomic number is equal to the number of protons Atomic mass is equal to the number of protons plus neutrons

8.  Ionic bond – strong electrical attraction between ions that bare opposite electrical charges (Fig. 2-2); ionic molecules dissolve easily in water (dissociate)  Covalent bond – bond formed between two atoms that share a pair of electrons (Fig. 2-3)

11.  Polar Covalent Bond – electrons are not shared equally (ex. H 2 O)  Non Polar Covalent Bond – electrons are shared equally (ex. C-H)

13.  Molecules that generally do not contain carbon; there are no C-H or C-C bonds; smaller than organic molecules  H 2 O is an inorganic molecule – “universal solvent”  Organisms are composed mainly of water

16.  Acid – a substance that releases H + (hydrogen ions); pH<7  Base (alkaline) – a substance that releases OH - (hydroxide ions) or decreases H + ; pH>7  Salt – substance composed of positively charged ions (not H + ) and negatively charged ions (not OH - ); usually neutral  Buffers – substances that react with strong acid or base to keep pH constant by absorbing or releasing H + or OH - as needed; helps to maintain homeostasis

18.  Carbohydrates – carbon + water – Fig. 2-6  glycogen – animals store energy in this carb.  Starch – plants store energy in this carb.

19.  Phospholipids – major component of cell membranes  Triglycerides – energy storage  Cholesterol – steroid lipid – component of cell membrane; precursor to steroid hormones

22.  Enzyme – protein that acts as a catalyst – Fig. 2-10  Co-enzyme – some enzymes don’t function unless a co-enzyme is present (vitamins may serve this function)