You guys are going to learn about chemistry today! Chemistry is basically just magic explained and is responsible

for the ridiculously long looks Brad and I gave each other in that janky old house

in my movie. Oh, and the part where my friend, Paulie, rapped with that weird

dude. TOP THAT!

Chapter 2- The Chemical Context of Life Song: “Top That” from Teen Witch

Chemical Foundations of BiologyChemicals are used

by animals for an array of reasons

Ex: Fig 2.1 Bombardier Beetle uses a boiling hot spray from glands in its abdomen as protection

Elements and Compounds Matter: Anything that takes up space and has massElement: Substance that cannot be broken down into

other substances by chemical reactions (92 total)Compounds: 2 or more elements combined by

chemical bonds

Essential/Trace Elements of Life Carbon, Oxygen,

Hydrogen, Nitrogen

Isotopes Atoms with the same

number of protons, but different numbers of neutrons

Radioactive isotopeNucleus decays

spontaneouslyUsed in biology to

date fossils, to follow atoms through the metabolism, used as tracers

Chemical BondsCovalent Bonds

Sharing of valence electrons by 2 atoms

Ex: Oxygen gas, Nitrogen gas

Polar Covalent BondsOne atom is slightly

more electronegative than the other so the molecule is slightly polar

Ex: Water (Fig 2.12)

Ionic BondsElectron is stripped

away from the partner by the more electronegative atom

Compounds formed by ionic bonds are called salts

Ex: NaCl Sodium Chloride (Fig 2.14)

Cation-Positive chargeAnion-Negative

Charge

Weak Chemical Bonds Hydrogen Bond (Fig 2.14)

Forms when a hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom

Van der Waals Occur when atoms and

molecules are very close together (atoms stick to one another)

Ex: Geckos walking up a wall surface

Chemical ReactionsReactants- Starting Materials Products –Ending materials

Ex: Photosynthesis (Fig 2.18)6CO2 + 6H2O C6H12O6 + 6O2