Chapter 2: Chem-Is-Try Elements and Compounds Chemical elements of life Atoms and Molecules Atomic structure and function Bonding and chemical reactions TOD: Methods box p.30 Fig 2.17 mimic molecules TOD: Methods box p.30 Fig 2.17 mimic molecules

Elements and Life Define element: Compound: SPONCH CaK ( ONCH 96% ) Trace elements (Fe, I) anemia, goiter—iodized salt, sea weed Crops too—nitrogen, calcium

Atoms and Molecules Quick review: electrons, neutrons, protons, orbitals, nucleus Atomic number Atomic mass (mass number) Dalton

Helium

Electron orbitals 1s 2s 2p (x, y, z)

The major elements of life

Covalent bonds Fig 2.10 (share electrons)

Polar Covalent Fig 2.11 Bonds * electronegativity

Ionic bonds (electron transfer +/- ions)

Hydrogen Bonds fig 2.14

Structure / Function Examples Mimic molecules

T.O.D: Radioactive Tracers in Bio. Label chemical substances within cells, are traceable Scientists can locate substances within an organism &/or follow metabolic processes.

Sources Campbell, Reece, Mitchell. Biology, 5 th Ed. 1999, Chap- ter one. Pgs Campbell, Reece, Mitchell. Biology, 5 th Ed. 1999, Presentations CD-ROM. Click art CD-ROM, Broderbund.

VIDEOS on the instructor’s disk

Molecular shape Structure / Function Examples

Fig 2.7 Energy Levels of Electrons light fluorescence photo- synthesis Energy Absorbed Energy Lost

Hierarchy of life