BIOL 1441 1st EditionExam # 1 Study Guide Lectures: 1 - 10Lecture 1 (January 15)Structure=function- Atom: smallest unit of matter that still retains the properties of an elemento Electrons (-)o Protons (+)o Neutrons (neutral) Protons/neutrons make up nucleuso ALL HAVE NEUTRAL CHARGE UNLESS OTHERWISE INDICATEDo # of protons= # of electrons- Matter: made up of elementso Anything that takes up space/has mass- Element: cant be broken down into other substances by chemical reactionso Trace element: required in minute quanitities Iron/iodine- Goiter: iodine deficiencyo Categorized by the # of atomso Carbon, oxygen hydrogen, nitrogen Make up about 96% of all living matter- Compound: substance consisting of 2 or more DIFFERENT elements combined in a fixed ratio- Atomic mass: weight of nucleus (neutrons + protons)o Electrons weigh almost nothingo Dalton (atomic mass unit): 1 proton or 1 neutron = 1 dalton- Atomic number: # of protonso All atoms of a particular element have the SAME number of protons- Isotopes: same elements but different # of neutrons (mass will change)o Atomic number stays the same (number of protons didn’t changeo Atomic mass changeso Radioactive isotopes: unstable Start spontaneously decaying Gives off particles/energy Give off proton-element changeEnergy:- When atoms collide- only the ELECTRONS interact- Energy: capacity to cause changeo Kinetic energy: energy of movemento Potential energy: energy matter possesses due to location or structure low energy=stable electrons have potential energy Electrons have greater potential energy, since the electrons are very attracted to the positively charged nucleus, so it takes more energy to keep them farther away from the nucleus in the outer valence shell. The closer the electron is to the nucleus, the lower the potential energy. MATTER MOVES TO THE LOWEST POSSIBLE STATE OF POTENTIAL ENERGY- Energy level: how much potential energy electrons possesso Correlates to the average distance from nucleus- Electron shells: energy levelso Electrons can move through themo Absorbing energy=moving farther away from nucleuso Losing energy= moving closer to the nucleusChemical properties:- Chemical behavior is determined by ELECTRON CONFIGURATION- Chemical behavior depends on the # of electrons in the outermost shell (VALENT SHELL)- Valence electrons: electrons in the outermost shell- Valence shells:o 1st shell: can hold 2 electronso 2nd shell: can hold up to 8 electronso 3rd shell: can hold up to 8 electronso Full valence shell: stable, unreactive, inerto Incomplete valence shell: unstable, reactiveo Shells are not actually real just a space- Orbital: pathways that the electrons move througho Each orbital can hold 2 electrons Shell 1: 1s(1st orbital) Shell 2: 2s(1st orbital)- 3p(3rd orbital)-fills up after 2sLecture 2 (January 17)- chemical bonds- Unpaired electrons=reactive- Atoms combine to fill their valence shellso Covalent: strongesto Ionic: 2nd strongesto Hydrogen: weakest- A covalent bond is a very strong chemical bond that occurs when one or more pairs of electrons are shared between two atoms.o Polar covalent bond: is a covalent bond where the electrons are not shared equally, so there is a charge (a water molecule)o Nonpolar covalent bond: is a covalent bond where electrons are shared equally so there is no charge (2 atoms of the same element)o Molecule: 2 or more atoms held together by a covalent bond single covalent bond: (hydrogen) molecule shares 1 electron- H---H Double covalent bond: (oxygen) molecule shares 2 electrons- O---O- Valence: the bonding capacityo The number of electrons it takes to fill the valence shell- Electronegativity: the attraction of an atom for the electrons in a covalent bond (CANT CHANGE)o The more electronegative an atom- the more strongly it pulls shared electrons to itselfHIGH ELECTRONEGATIVITY:- Oxygen- NitrogenLOW ELECTRONEGATIVITY:- Hydrogen- CarbonNON-POLAR: (pairs of the same element bonded)- O—O- N—N- C—C- H—H- C—HPOLAR:- O—C- O—H - N—C- N—H- Water is a polar moleculeo Delta: partial charge δWhat is an ionic bond?- Ionic bond: is also a strong bond that forms between two atoms of different charges. (one negative and one positive) o Ex. Sodium chlorideo Ion: a charged atom/molecule that has lost or gained an electron Lose electron= positive charge: CATION Gain electron= negative charge: ANION- TRANSFERRING THE ELECTRON IS NOT THE FORMATION OF AN IONIC BONDo Transfer of electron creates an ION- Ionic compounds: saltso In nature found as crystals: 3D lattice structureo Only has a RATIO of elements NaCl- 1:1 MgCl2- 1:2What is a hydrogen bond?- Hydrogen bond: relatively weak bonds between polar moleculeso Hydrogen atoms covalently bonded to one electronegative atom in another polar covalent bondo Easy to pull apart/replicateChemical reactions- Chemical equilibrium: when the rate of forming and breaking (forward/reverse) chemical bonds in a reaction is the same but not the quantities of the reactants and products- Rate of reaction: concentration of reactantso More reactants= for frequent collisions so more reaction/more bonds formedLecture 3 (January 22)- water*Hydrogen bonding is responsible for water properties*Water is the only substance that naturally exists in all 3 states (liquid, solid, gas)- Water properties:o Cohesiono Moderation of temperatureo Expansion upon freezingo Universal solvent- Cohesion: holds substances togethero H2O molecules are attracted to each other- b/c of Hbondso Contributes to the transport of water and dissolved nutrients against gravity in plants Water evaporates from leaves Upward pull is transported through all cells from rootso Adhesion: clinging of one substance to another Water adheres to walls of the cellso Surface tension: measure of how difficult it is to stretch/break the surface of a liquid- Moderation of temperature:o Water= heat band-stores heat Can lose and gain lots of heat and not change much in tempo Heat: TOTAL amount of kinetic energy due to the molecular motion in a body of matter Is a form of energy-depends on the volume of the mattero Temperature: AVERAGE of kinetic energy Average speed of molecules increase-temperature increaseso Heat and temp are related but NOT the same Ex. Humans have a higher temperature than the ocean, but the ocean has more heat