Chemistry Everything in life is either chemistry or physics Dr. M. Diamond

Atoms Nucleus –protrons (+) charge neutrons no charge Electrons –negative charge –orbit in shells

Isotopes Different numbers of neutrons –Mass # = protons + neutrons –Atomic # = protons

Radioisotopes Decay at a predictable rate Beta particle released turning a neutron into a proton Half-life – the amount of time it takes for half of the radioisotopes to decay –Half-life for C 14 = 5730 yrs. – good for dating things that are up to about 60k yrs Should never reach 0

What are you? Mostly H, O, C, N H 9.5% C 18.5% O 65% N 3.2%

Molecules Two or more atoms bonded together May be compound (different types of atoms) Compounds have properties different from their components

Bonding Ionic – electron donation

Bonding (your mother told you to SHARE!) Covalent - methanewater

Bonding (weak and weaker) Hydrogen (weak)Van der Waal’s (weaker)

More on covalent bonds Electrons –Shared equally results in a non-polar molecule (e.g., carbon dioxide) –Shared unequally results in a polar molecule (e.g., water)

Water Polar molecule Water molecules are attracted to each other And to other polar molecules

Water solvency Water attracts other polar molecules Repels non-polar An excellent solvent –Because of polarity –Most chemical substances will dissolve in water –More will dissolve in water than any other liquid

Interactions

More Interactions

How does this affect cell membranes? Orientation of mem- brane components Orientation of proteins in membrane

Other properties Cohesion – attraction to other water molecs. Adhesion – attraction to other surfaces

Heat Capacity The quantity of heat required to produce a unit change of temperature (1 o C) in a unit mass (1 g) of material Very high in water because of H bonding

What is pH? Concentration of H+ ions (or OH-) pH = the negative log of the H+ ion concentration in moles/L The higher the H+ concentration, the lower the pH (acidic) The lower the H+ concentration (and higher OH- conc.) the higher the pH (basic or alkaline) pH 7 is neutral

More on pH Here’s the math explanation

Buffers Help maintain pH –Accept xs H + or –Donate H + –Very important for cell functioning