Characteristics of Life:
â—‹ Cells, energy use/metabolism, response to environment, regulation/homeostasis,
growth & development, reproduction, evolution
â— Levels of Organization:
○ Cells → tissues → organs → organisms → population → community →
ecosystem → biosphere
â— Domains
â—‹ Archaea
â—‹ Bacteria
○ Eukarya (eukaryotic) → Protista, Fungi, Plantae, Animalia
■Kingdom → Phylum → Class → Order → Family → Genus → Species
â— Scientific Method
â—‹ Types: Controlled (independent/dependent variable) vs Comparative (predict
differences)
â—‹ 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
â— 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
â– Averaged & weighted for the proportion
■Radioactive → unstable & emit particles
â— Orbitals
â—‹ 2 e- in each, octet rule
â—‹ E- gain energy move farther, lose energy move closer
â— Chemical Bonds
○ Covalent → share electrons, the strongest
â– H: 1ve,
â– C: 6ve, 4cb
â– N: 7ve, 3cb
â– O: 8ve, 2 cb
○ Nonpolar Covalent → share electrons equally, same EN (.2-.5 difference)