Presentation on theme: "Unit 2: Matter and Energy"— Presentation transcript:
1 Unit 2: Matter and Energy A Summary of How Theories Develop in Science:– based on a series of verifiable observations & measurements.leads to aconclusionbased oninductivereasoning-tests mustbe...– other people must be able to repeat and verify or reject tests.a theory arisesscientifictheoriesenableresearchers tomake...– that guides research and opens-up new questions.conclusions drawn on evidence can be tested with an experiment or additional observations.
2 Identify what is wrong with each of the following statements. 1.Everybody knows that gravity exists. There is so much proof for the Law of Gravity that it will not change.2.Although many scientists believe in evolution, there are still many things that cannot be explained by evolutionary biologists. Therefore, it is just a theory.3.After completing our lab, we proved that the theory of enzyme activity was right.
3 – the basic unit of matter Basic Chemistry– the basic unit of matterElectron configuration of oxygen– center of the atom– positively charged particles (+)– particles that carry no charge– negatively charged particles (-), 1/1840 the mass of a proton (equal, but opposite charge)– spaces that electrons have the greatest probability of being found
5 The Element Carbon on the Period Table 6Atomic numberCWhy is the atomic mass of carbon not exactly twelve?Carbon12.011Atomic massAtomic number –Atomic mass –Go to Section:
6 The 6 most common elements that make up living organisms: Elements Found in Biological OrganismsThe 6 most common elements that make up living organisms:CHONSP or SPONCHThe Periodic Table of Elements
7 Compounds and Chemical Bonds Two Main Types of Chemical Bonds:Ionic Bonds –Covalent Bonds –
8 Why Ionic Bonds Are Important to Life Break apart easily in waterThe ions are used to transfer positive or negative charges in cells (i.e. allows information, materials, and short-term energy to be exchanged)
9 Why Covalent Bonds Are Important to Life Store energy in the bonds (this energy can be used for growth, movement, etc by an organism)Do not break apart in water (the bodies of plants and animals are mostly water – glucose will not release its energy)Form the building blocks of life (proteins, fats, etc. are made of covalent bonds)
10 2-2 Properties of WaterWater is the single most abundant compound in most living things and it possesses many special properties. Water is one of the few compounds that is liquid at the temperatures found over much of the Earth’s surface. When water does freeze, it expands, becomes less dense than liquid water, and floats.
11 Polarity of Water Water is a polar molecule – Oxygen has more electrons, so it is more negatively charged (i.e. it is electronegative and pulls electrons to it)Hydrogen has fewer electrons, so it is more positive than negatively charged
12 Hydrogen Bonding in Water – weak bond formed with a positively charged hydrogen atom and other negatively charged atomsWaters polarity and hydrogen bonds give it unusual propertiesIt easily forms a solid (ice), liquid, and gas (vapor).Cohesion – a property dependent upon the strength of attractive forces between molecules of the same substance (water to water)Adhesion – a property dependent upon the strength of attractive forces between molecules of different substances (water to glass)
13 Why Water Is Necessary to Life Cl-Cl-Na+Na+WaterWaterWater is a solvent –Solute –Water breaks some chemicals apart, allowing atoms to interact and move around, so chemical reactions can take place easily.Go to Section:
14 The Chemistry of Carbon Figure 2-11 Carbon CompoundsButadieneMethaneAcetyleneIsooctaneBenzeneCarbon has 4 valence electrons, allowing it to bond to 4 other atomsCarbon forms strong covalent bondsCarbon bonds easily with other carbon atoms, hydrogen, oxygen, nitrogren, sulfur, and phosphorous =Organic Compounds -Organic compounds interact to perform the basic functions of life
15 Macromolecules - Macromolecules are built buy joining smaller molecules together. Monomers - small unit that joins together with other small units to form polymers.Polymers - large compound formed from combinations from many monomers.
16 CarbohydratesStarchGlucoseCarbohydrates - compounds made up of carbon, hydrogen, and oxygen atoms usually in a ratio of 1:2:1.Functions as the energy source for most living thingsMonosaccharide – simple sugar molecules (glucose, fructose, galactose)Polysaccharide – chains of monosaccharidesGlycogen – stored in muscles and the liver of animalsStarch – stored in plantsCellulose – found in the stalks of plants, provides strength and rigidity
17 LipidsLipids - macromolecule made mainly from carbon and hydrogen atoms; includes fats, oils and waxes.Functions as an energy source and makes up part of the cell membrane and steroid hormonesFormed when glycerol binds to fatty acidsInsoluble in waterSaturated fats – lipids that have the maximum possible number of hydrogen bondsUnsaturated fats – lipids that contain some double bonds
18 Nucleic AcidsNucleic acids - macromolecule containing hydrogen, oxygen, nitrogen, carbon, and phosphorous.Functions as genetic structure, transmits hereditary informationNucleotide – building blocks of nucleic acidsTypes of nucleic acidsDNARNAStructure of DNA
19 ProteinsAminoacidsProteins macromolecule that contains carbon, hydrogen, oxygen, and nitrogenFunction as enzymes, hormones, builds the structure in bones, muscle and organsAmino acid – the building blocks of proteins
20 Amino AcidsAmino groupCarboxyl groupGeneral structureAlanineSerineAmino acids - compounds with an amino group (-NH2) on one end and a carboxyl group (-COOH) on the other end.There are 20 different amino acids that can combine to form proteins. Proteins are made up hundreds of amino acids bonded together and then folded into a particular shape.
23 Chemical ReactionsChemical Reactions - a process that changes one set of chemicals into anotherMetabolism – the sum of all the body’s chemical reactionsEnergy-Absorbing ReactionEnergy-Releasing ReactionCO2 + H2O C6H12O6 + O2C6H12O6 + O2 CO2 + H2OProductsActivationenergyActivation energyReactantsReactantsProductsExample – Photosynthesis (synthesis)Reactants = CO2 + H2OProducts = C6H12O6 + O2Example – Cell Respiration (decomposition)Reactants = C6H12O6 + O2Products = CO2 + H2O
24 Energy in ReactionsReaction pathwaywithout enzymeActivation energywithout enzymeReactantsActivationenergywith enzymeReaction pathwaywith enzymeProductsActivation energy – the amount of energy needed to start a chemical reactionWhat is an enzyme?
25 Enzymes Enzyme – complex proteins that lower the activation energy Speed up the chemical reactions in a cellLower the temperature needed for the reaction to occurAct as catalysts – speed up reactions, but are not used up (can be used over and over)
26 Factors that Affect Enzyme Action TemperatureSurface AreapHExplain how each of these might affect the function of an enzyme
27 The pH ScaleThe pH scale indicates the concentration of H+ ions in solutionAt pH 7, the concentration of H+ ions and OH- ions is equalAcid – any compound that forms H+ ions in solutionBase – any compound that produces OH- ions in solutionBuffer – a weak acid or base that can react with strong acids or bases to prevent sharp, sudden changes in pHFluids in most cells must be kept between 6.5 and 7.5 or the reactions in cells will be effectedOven cleanerBleachAmmonia solutionIncreasingly BasicSoapSea waterHuman bloodNeutralPure waterMilkNormalrainfallAcid rainIncreasingly AcidicTomatojuiceLemon juiceStomach acid