Biology 12 Biological Molecules

Cheat Sheet prefix/suffix -ology = the study of Cyto-/cyte = cell Hydro-/hydrate = water Lyso- = split Lysis = break apart Pod/ped = foot Thermo = temperature Phobia/-phobic = fear/hating -phylic / -philia = loving Poly = many Iso = same Soma - / -some = body Chrome=colour

Atomic Bonding Ionic Bonding Covalent Bonding Polar Bonds/ Hydrogen Bonds/ H-Bonds

Ionic Bonding A metal + non-metal Metal will give all e- in its outer shell to a non- metal so that both have a full shell

Covalent Bonding 2 non-metals will share electrons Both atoms share the electrons equally (non-polar, hydrophobic) Because the e- are shared equally by both atoms, the molecule is electrically “neutral” The shared electrons are attracted equally to both nuclei because they have the same charge The electrons are not shared equally (polar, hydrophilic)

Polar Bonds/ Hydrogen Bonds Bond between 2 polar molecules The positive end of one is attracted to the negative end of the other Ie: the bond that hold the water molecules together

Other Notes Polar mixes with Polar Non-Polar mixes w/ Non-Polar Ie: Water + Sugar Non-Polar mixes w/ Non-Polar Gasoline + oil Polar and Non-Polar do NOT mix Water and Oil

Acid, Bases and Buffer Polarity can cause some molecules to split apart or DISSOCIATE when mixed with water Ie: H2O -> H+ + OH- Note: [ ] Concentration Ie: [salt] = salt concentration

Acid, Bases and Buffer Acids- any compound that dissociates in water to release H+ ions Bases – any compounds that dissociates in H2O to release OH- ions [OH]>[H+] When [H-] and [OH-] are equal to each other, what is the solution called?

Buffer Compounds that pick up excess H+ or OH- to maintain a constant pH of a solution Essential to living things In humans, buffers help us maintain homeostasis A common buffer that we have is HCO3-

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