Chapter 2 Chemistry of Life- Atoms, Ions, Moleculeso Chemical Elements: the simplest form of matter to have unique chemical properties Protons, neutrons, and electrons Atomic number: number of protons All naturally occurring elements- 98.5% of the human bodyo Carbon, hydrogen, nitrogen, phosphorous, oxygen, calcium- 0.8% of the human bodyo Potassium, sodium, sulfur, chlorine, magnesium, iron- 0.7% of the human body (trace elements)o Chromium, cobalt, copper, fluorine, Iodine, manganese, molybdenum, selenium, silicon, tin, vanadium, zinc Minerals: Inorganic molecules that are extracted from the soil by plants and passed up the foot chain to humans- 4% of the body weighto Atomic Structure Neils Bohr: planetary model Protons p+, neutrons n0, electrons e- Proton & Neutron- 1 amu Electrons- ½ amu- Electron Shello 7 (human body doesn’t exceed 4)- Valence electrons: determine chemical bonding properties of an atomo Isotope & Radioactivity Isotope: variety within an element - Same number of protons, but different number of neutrons and therefore a different atomic mass Radioactivity: decaying of radioisotopes that are unstable- All elements have at least one radioisotope Radiation: - Low energy is harmless- High energy: ejects electrons from atoms converting atoms into ionso Ionizing radiation: creates dangerous free radicals & ions in human tissueo Mutagenic & carcinogenico Alpha particles = heliumo Beta particles = electrono Gamma rays- Physical half lives: the time required for 50% of its atoms to decay to a more stable state- Biological Half Life: time required for half of it to disappear from the bodyo Ions, Electrolytes, & Free Radicals Ions are charged particles with unequal number of protons and electrons- Form because elements with 1-3 valence electrons tend to give them up- 4-7 valence electrons gain themo Ionizationo Cations & anions- Some exist in multiple ionized forms Electrolytes: ionize in water & form solutions capable of conducting electricity- Electrical activity in brain, muscles, & heart Free Radicals: chemical particle with odd number of electrons- Produced by metabolic reactions, radiation, and chemicals- Short-lived & combine quickly- Cause lots of damage- Antioxidants: neutralize free radicalso Deficiencies cause heart attack, muscular dystrophy, and sterilityo Molecules and Chemical Bonds Molecules are chemical particles composed of two or more atoms united by a chemical bone- 2 or more elements is a compound- Represented by a molecular formula o Different arrangements of their atoms is an isomer- Molecular weight: sum of all the atomic weights of its atoms Chemical Bonds: - Ionic: attraction of an anion & cation o Weak and easily disassociatedo δ+ δ-- Hydrogen Bond: Week attraction between slightly positive hydrogen and slightly negative oxygen or nitrogen- Van der Waal: weak, brief attractions between neutral atomso Random fluctuationso 1% as strong as a covalent- Water & Mixtureso Mixture: substances that are blended together but not chemically combined Retains chemical propertieso Water Most mixtures consist of chemicals dissolved or suspended in water Solvency: ability to dissolve other chemicals- Hydrophillic: dissolves in watero Polarized or charged Adhesion: one substance ability to cling to another Cohesion: molecules of the same substance cling to each other Thermal Stability: helps stabilize internal temperature of the body- High heat capacity- Calorie is 1 g of water increased temperature by 1° Co Solution, Colloids, & Suspensions Solution: solute + solvent- Particles are under 1 nm for the solute mixed with a more abundant solvent- Particles do not scatter in light noticeably - Pass through most selectively permeable membranes- Doesn’t separate Colloids: mixture of protein and water- 1-100 nm- Scatter in light, usually cloudy- Too large to pass through selectively permeable membrane - Small enough to remain mixed Suspension: - >100 nm- Cloudy or opaque- Too large to pass selectively permeable membrane- Usually separates Emulsion: suspension of one liquid in anothero Measure of Concentration Weight per volume- (g/L)- Percentageso Specify to weight or to volume- Molarityo Mols/ L = M Electrolyte Concentration: - Takes charges into account- Equivalent (eq)- 1 eq neutralizes 1 mole of H+- eq/L usually less that one litero Acids, Bases, & pH Acids: proton donors Bases: proton acceptors pH: derived from molarity- Negative logarithm of hydrogen ions- Molarity (-log[H+])- Energy & Chemical Reactions- Energy & Worko Energy is the capacity to do work Work is to move something (muscle to molecules) Breaking and forming bonds Potential and Kinetic Energy- Chemical energy is potential energy stored in chemical bonds- Heat is kinetic energy of molecular motiono Temperature of a substance is a measure of the rate of motion- Electromagnetic energy is kinetic energy of moving packets of radiation called photons- Electrical energyo Potential Energy when charged particles have accumulated o Kinetic Energy when charged particles begin to move- Free energy: Potential energy in a system to do useful worko Classes of Chemical Reactions Chemical reactions: covalent or ionic bonds is formed or broken- Chemical equation: Reactant  Product- Decomposition: large molecule breaks down- Synthesis: smaller particles come together- Exchange: Two molecules exchange atoms or a group of atoms- Reversible: both wayso Law of mass action: reactions proceed from the side with the greater quantity reactants to the less quantityo Exists in a state of equilibriumo Reaction Rates Concentration: rates increase when the reactants are more concentrated- More crowded and more collisions Temperature: increase in temperature increases reaction rates- Greater force, greater collisions Catalyst: temporarily bind to reactants and should hold them in a favorable position to reacto Metabolism: all reactions in the body Catabolism: energy releasing decomposing reactions- Break covalent bonds- Exergonic: energy releasing Anabolism: energy storing reactions; synthesis reactions- Require energy input: endergonic - Driven by catabolic reactions Redox Reactions:- Oxidation: any chemical reaction in which a molecule givesup an electron and releases energyo Whatever molecule takes up the electron: oxidizing agento Oxygen is often the acceptor- Reduction: a chemical reaction in