Chapter 2 The Chemical Context of Life “Hey… psst, did Mr. Slagel teach us the chemical formula for sand….. “Are you kidding…. It is still summer, I am still on the beach (at least in my mind).

Actually, Chemistry is THE FOUNDATION of all BIOLOGY

Atoms  Smallest particle of elements.

Element  Matter made up of only one type of atom.  92 natural elements.  Each element has a symbol.

Question? Which Elements are necessary For Life? Life requires about 25 chemical elements.

Macroelements Elements needed in large amounts or quantities. Examples: C HOPKNS CaFe Mg NaCl ControlMinus Nitrogen

Trace Elements - required by an organism in minut quantities.  ex. Fe, I, Mg Goiter – minus Iodine

Atomic Particles Protons + charge, 1 Dalton mass Neutrons no charge, 1 Dalton mass Electrons - charge, essentially no mass

Isotopes - same # p + ’s differing # of neutrons. - Uses in biology as tracers

PET Scan

Electron Configuration and Chemical Properties - An atom’s electron configuration determines it’s chemical behavior

Energy The ability to do work.

Potential Energy Is the energy that matter stores because of its position or location. Electrons have potential energy because of their position relative to the nucleus.

Electron Orbitals The three dimensional space where an electron is found 90% of the time. Different orbitals have different shapes. Each orbital can hold only 2 electrons.

Chemical Bond Types Nonpolar Covalent Polar Covalent Ionic Hydrogen Van der Waals

Atoms combine by chemical bonding to form molecules - Ionic Bond - (weak in the presence of water) Hydrogen Bond- (weak) bonds between molecules.

A molecule’s shape determines function. Is this an emergent property? Shape is important b/c it determines how molecules respond to one another… complementary shaped molecules are able to bind to each other!