2 Section 1 – The Nature of Matter Atoms are the basic unit of matter.Subatomic particles that make up atoms are protons, neutrons, and electrons.Protons – positively charged particlesNeutrons – carry no charge, neutralProtons and neutrons are found in the nucleus of the atom
3 Electrons Electron – negatively charged particle In constant motion in the space surrounding the nucleus.
4 ElementsElement – pure substance that consists entirely of one type of atom.Represented by a one- or two- letter symbol.Elements are arranged into the periodic table.
5 Chemical CompoundsA chemical compound is a substance formed by the chemical combination of two or more elements in definite proportions.
6 Chemical BondsIonic bonds – formed when one or more electrons are transferred from one atom to another.Covalent bonds – formed when electrons are shared between atoms.Van der Waals forces – when molecules are close together, a slight attraction can develop between oppositely charged regions of nearby molecules. These attractions are not as strong as ionic or covalent bonds.
7 Section 2 - Properties of Water Polarity – a molecule in which the charges are unevenly distributed is a polar molecule.A water molecule is polar because there is an uneven distribution of electrons between the oxygen and hydrogen atoms.
8 Hydrogen BondsA single water molecule may be involved in as many as four hydrogen bonds at the same time.Cohesion: an attraction between molecules of the same substance.Adhesion: an attraction between molecules of different substances.
9 MixtureMixture – a material composed of two or more elements or compounds that are physically mixed together but not chemically combined.
10 Solutions Solution – all components are evenly distributed throughout. Solute – the substance that is dissolvedSolvent – the substance in which the solute dissolves
11 Suspensions Suspension – mixture of water and non-dissolved materials. Materials will separate into pieces but do not settle out
12 Acids, Bases and pHThe pH scale – a measurement system that indicates the concentration of H+ ions in a solution.Ranges from 1 – 147 is neutralUnder 7 is acidicAbove 7 is basic
13 AcidsAny compound that forms H+ ions in solutions.pH value below 7
14 Bases Any compound that produces hydroxide (OH-) ions. pH value above 7
15 BuffersWeak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes in pH.Help control pH and retain homeostasis in the body.
16 Section 3 – Carbon Compounds Macromolecule: LARGE carbon moleculePolymer: Large molecule formed when many smaller molecules bond together
17 Carbohydrates 2 H atoms for every O & C 1. Simplest carbs: Called Monosaccharides (one sugar)-Ex: glucose; fructose- 2. Disaccharides – two sugars-Sucrose (glucose + fructose)- 3. Polysaccharides – many sugars-Starch, glycogen, and cellulose
18 LipidsLipids: Fats; Organic compounds that have a large proportion of C-H bonds and less O than carbs. Insoluble in water because lipids are nonpolar Saturated Fat: Animal fatsUnsaturated Fat: Oils
19 ProteinsA large, complex polymer composed of carbon, hydrogen, oxygen, nitrogen, and usually sulfur; have an “R” group that makes each differentMade from amino acids 20 common amino acids Proteins are the building blocks of many structural components
20 ProteinsAmino Acids are linked together when an H-group and –OH group are removed to form waterThe covalent bond formed between A.A. is a PEPTIDE BOND
21 Nucleic AcidsA complex macromolecule that stores cellular info. in the form of a codeNucleic acids are made up of smaller subunits called NucleotidesNucleotides consist of three basic parts:1. Nitrogen-containing base2. Pentose sugar3. Phosphate group
22 Types of Nucleic Acids 1. DNA: Deoxyribonucleic acid Master copy of organism’s genetic info.Contains instructions used to form organism’s enzymes and proteins2. RNA: Ribonucleic acidForms a copy of DNA for use in making copies and proteins
23 Section 4 - Chemical Reactions Chemical formulas describe the substances in the reaction and arrows indicate the process of changeReactants – starting substances on the left side of the arrowProducts – substances formed during the reaction on the right side of arrowArrow can be read as “yields” or “react to form”
24 Energy in Reactions Key to starting a chemical reaction is energy Energy in the form of heat is needMost compounds in living things cannot undergo chemical reactions without energy
25 Activation EnergyMinimum amount of energy needed for reactants to form products in a chemical reaction
26 Energy Change in Chemical Reactions In every chemical reaction, there is a change in energy due to the making and breaking of chemical bondsExothermic reactions – energy of the product is lower than the energy of the reactantsEnergy is released in the form of heatEndothermic reactions – energy of the products is higher than the energy of the reactantHeat energy is absorbed
29 EnzymesCatalyst – substance that lowers the activation energy needed to start a chemical reactionEnzymes – special proteins that are the biological catalysts that speed up the rate of chemical reactions in biological processesEssential to lifeNot used up by the chemical reactionCan be used againMost enzymes are specific to one reaction
30 Enzymes Substrates – reactants that bind to the enzyme Active Site – specific location where a substrate binds on an enzymeThe active site and substrates have complementary shapesOnly the substrate with the same shape as the active site will bind to the enzymeExample : Lock & Key
31 EnzymesOnce the substrates bind to the active site, the site changes shape and forms the enzyme-substrate complexThe new complex helps chemical bonds in the reactants to be broken and new bonds are formedThe substrates react to form productsThe enzyme then releases the products
32 EnzymesFactors such as pH, temperature, and other substances affect enzyme activityEnzymes affect many biological processesExamples:PhotosynthesisRespirationSnake biteFruit ripening