A Note on Lecture 1-You do not need to memorize the themes of biology, but you should understand how they apply to just about all the topics that weve covered. -Thats why theyre themes!

Parts of an Atom

Bonds (in order of strength)-Covalent bond-atoms share electrons to fill their valence shells. -Ionic bond-attraction between ions (which were formed by gaining or losing electrons entirely)-Hydrogen bond-relatively weak bond between partial charges. -Van der Waals Interactions-weakest bond which form due to the fact that molecules like to stick together.

Polarity and Bonding-Unequal electronegativity causes the covalent bond to be polar. -Polar=Hydrophilic=Loves interacting with water=Forms hydrogen bonds-Nonpolar=Hydrophobic=Hates interacting with water=Does not form hydrogen bonds

Water-Properties of the 3 states of water-Water is a polar-Polar molecules form hydrogen bonds-Water is the solvent of life

Heat/Temperature-Specific heat-the amount of heat that must be absorbed or lost for 1g of that substance to change its temperature by 1 C. Water has a high specific heat. -Evaporative Cooling-molecules with the most energy leave a liquid, causing the average energy (temperature) of the liquid to decrease.