Chemical Basis of Life
BIOLOGY 22
MODULE 1 – Chemical Basis of Life v2.0 * Levels of Organization – biological functions are ultimately based on the properties of atoms and molecules * Subatomic particles – neutrons, electrons, protons * Atoms * Compounds * Complexes of compounds * Organelles – bodies within cells that perform specific functions * Cell * Specific combination of organelles * Can metabolize and reproduce * Least elaborate living structure * Significance of Chemistry/Physics in Biology * Biology based on chemistry * Chemistry based on physics * Important Concept in Chemistry * Matter, Atoms, Atomic Structure * Matter – anything that has mass and occupies space (e.g. solid, liquid, gas, plasma) * Atomic Theory – Dalton * All matter is made of atoms * All atoms are made of subatomic particles * Atoms – units of matter * Bohr – proposed structure of atom (similar to solar system) * Parts of atoms * Nucleus * Proton * Neutron * Electron – in an electron cloud * Important concepts * Electrons are arranged in shells according to energy levels * Filled innermost shell – 2 electrons
Filled outermost shell – 8 electrons * Same number of valence = similar chemical behaviors
* Elements * Pure substances made of one kind of atom * Cannot be decomposed * Compounds / Molecules * Chemical reaction – processes where atoms combine/break with other atoms * Molecule – two or more atoms, may be same atoms (e.g. H2) * Compound – molecule containing at least 2 kinds of atoms (e.g. H2O) * Chemical Bonds * Ionic Bond * One atom gains electrons, one atom loses electrons * Bond strength = 5-10 kcal/mol * Cations – atom that loses electrons (+)
Anions – atom that gains electrons (-) * Covalent Bond * Two or more atoms share electrons * Electrons behave as if they belong to each atom * Bond strength =
MODULE 1 – Chemical Basis of Life v2.0 * Levels of Organization – biological functions are ultimately based on the properties of atoms and molecules * Subatomic particles – neutrons, electrons, protons * Atoms * Compounds * Complexes of compounds * Organelles – bodies within cells that perform specific functions * Cell * Specific combination of organelles * Can metabolize and reproduce * Least elaborate living structure * Significance of Chemistry/Physics in Biology * Biology based on chemistry * Chemistry based on physics * Important Concept in Chemistry * Matter, Atoms, Atomic Structure * Matter – anything that has mass and occupies space (e.g. solid, liquid, gas, plasma) * Atomic Theory – Dalton * All matter is made of atoms * All atoms are made of subatomic particles * Atoms – units of matter * Bohr – proposed structure of atom (similar to solar system) * Parts of atoms * Nucleus * Proton * Neutron * Electron – in an electron cloud * Important concepts * Electrons are arranged in shells according to energy levels * Filled innermost shell – 2 electrons
Filled outermost shell – 8 electrons * Same number of valence = similar chemical behaviors
* Elements * Pure substances made of one kind of atom * Cannot be decomposed * Compounds / Molecules * Chemical reaction – processes where atoms combine/break with other atoms * Molecule – two or more atoms, may be same atoms (e.g. H2) * Compound – molecule containing at least 2 kinds of atoms (e.g. H2O) * Chemical Bonds * Ionic Bond * One atom gains electrons, one atom loses electrons * Bond strength = 5-10 kcal/mol * Cations – atom that loses electrons (+)
Anions – atom that gains electrons (-) * Covalent Bond * Two or more atoms share electrons * Electrons behave as if they belong to each atom * Bond strength =