Characteristics of Life:

○ Cells, energy use/metabolism, response to environment, regulation/homeostasis,

growth & development, reproduction, evolution

● Levels of Organization:

○ Cells → tissues → organs → organisms → population → community →

ecosystem → biosphere

● Domains

○ Archaea

○ Bacteria

○ Eukarya (eukaryotic) → Protista, Fungi, Plantae, Animalia

■ Kingdom → Phylum → Class → Order → Family → Genus → Species

● Scientific Method

○ Types: Controlled (independent/dependent variable) vs Comparative (predict

differences)

○ Only can prove a hypothesis wrong, not 100% correct

○ Scientific Hypothesis (observation) → Theory (phenomenon)→ Law (universally

confirmed)

○ Can’t use this method for historical events

● Atoms (give elements their properties)

○ Nucleus → proton & neutrons (mass of 1)

○ Orbitals → Electrons (mass of 0)

○ C,H,O,N → 95% of living matter

○ Atomic number → number of protons (= electrons)

○ Atomic weight → sum of neutrons & protons

○ Isotopes → atoms of the same element, different # of neutrons

■ Averaged & weighted for the proportion

■ Radioactive → unstable & emit particles

● Orbitals

○ 2 e- in each, octet rule

○ E- gain energy move farther, lose energy move closer

● Chemical Bonds

○ Covalent → share electrons, the strongest

■ H: 1ve,

■ C: 6ve, 4cb

■ N: 7ve, 3cb

■ O: 8ve, 2 cb

○ Nonpolar Covalent → share electrons equally, same EN (.2-.5 difference)