2 2.1 The nature of matterAtom: the smallest particle of an element that has the properties of that elementAtom is made of three subatomic particles:Proton * Positive, nucleusElectron * Negative, outside nucleus in energy levelsFirst energy level -- 2eSecond energy level -- 8eThird energy level -- 18eNeutron * No charge, nucleus
5 Number of protons usually is equal to the number of electrons so that the overall charge of an atom is neutral!! If atoms of the same element have different number of neutrons, they are called isotopes! EX. C - 12 , C - 13, C - 14When two or more atoms of different elements are chemically combined you create what is called a compound. EX. Water
6 Compounds can be made with three different kinds of bonds: CovalentShare electrons to be stableStrongest and most common bondMolecule: group of atoms held together with covalent bonds with no overall chargeVan der Waals forces (what holds molecules together)
7 Ionic Hydrogen Gain / lose electrons to be stable Ion: a charged particleLess abundant in living things than covalent bondsHydrogen
8 Mixtures & SolutionsMixture: a combination of substances in which the individual components retain their own properties Solution: a mixture in which one or more substances are distributed evenly in another substanceTwo parts to every solution:Solute --- What is being dissolvedSolvent -- What is doing the dissolving * Most common... WATER
9 pH pH: a measure of how acidic or basic a solution is Acid: substance that forms H+ ions in water0 - 7Base: substance that forms OH- ions in water7 – 14
11 Acids & Bases Acids Bases Higher concentration of H+ ions pH value less than 7Sour tasteReact with metalsBlue litmus paper will turn red if an object is an acidLower concentration of H+ ionspH value more than 7Bitter tasteSlipperyTurn red litmus paper blue if an object is a base
12 2.2 Water and DiffusionPerhaps the most important compound in living organisms is water!Properties of water:PolarityHas a positive and negative endGives water its dissolving propertyResists Temperature ChangesWater expands when it freezesAdhesion Graduated cylinderAdhesion is greater between glass & water than water & water!
13 2.3 Carbon CompoundsThe one element that defines living organisms is Carbon!Carbon has four electrons in its outermost shell; therefore, it can combine with almost every other elementAny compound that contains carbon is considered to be an organic compound!If it does not contain carbon it is inorganic.
14 Four types of Organic compounds: Carbohydrates:Made of C, H, O (C to H ration is 2 to 1)Monomer: monosaccharideFunction: Provide quick energyEX. Glucose: how animals store foodStarch: how plants store foodCellulose: composes cell walls of plants
15 2) Lipids Made of C, H, O --- (C to H ratio higher than 2 to 1) Monomer: Glycerol & 3 fatty acidsFunction: 1) Store energy 2) Insulation 3) ProtectionEX. Fats and Oils
16 3) Proteins Made of C, H, O, N, Sulfur Monomer: Amino Acid 20 AAFunction: 1) Build Muscle 2)Transportation (blood -- hemoglobin) ) Speed up chemical reactions (enzymes)
17 4) Nucleic Acids Made of C, H, O, N, Phosphorus Monomer: Nucleotide Function: Store genetic informationEX. DNA (Deoxyribose Nucleic Acid) – MasterRNA (Ribose Nucleic Acid) -- Copy of DNA
19 2.4 Chemical Reactions and Enzymes Chemical reaction = changes one set of chemicals into another set of chemicalsChemical reactions have two parts:ReactantsProductsCO2 + H2O H2CO3Reactants Product
20 Enzymes Enzymes are proteins that act as a biological catalyst. Catalyst: a substance that speeds up the rate of chemical reactionEnzymes speed up chemical reactions that take place in the cell.
21 Enzyme Action The enzyme-substrate complex Enzymes are substrate specific.They act like a lock and key.Enzymes will only catalyze their substrates.Regulation of Enzyme ActivityEnzymes can be affected by:HeatpHConcentration of SubstrateProteins that turn enzymes “on” and “off”
22 Example of what an enzyme does! How enzymes workPotato + Peroxide water + oxygen (catalase)
23 Where are enzymes? Enzymes regulate many chemical reactions such as: PhotosynthesisCellular respirationDigestionEnzymes are reusableOnce they work with one substrate they release and go to another substrate.