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Unit 2 Chemical Basis for Life Chapter 6 Chemistry in Biology Section Section Section Section 1: 2: 3: 4: Atoms, Elements, & Compounds (p. 148-155) Chemical Reactions (p. 156-160) Water & Solutions (p. 161-165) The Building Blocks of Life (p. 166-171) Section 1 Atoms, Elements, and Compounds Objectives Living things consist of atoms of different elements Ions form when atoms gain or lose electrons Atoms share pairs of electrons in covalent bonds The atom The atom is the smallest basic unit of matter Atoms are very small The atom There are three parts of a an atom Subatomic particle Charge Location Proton Positive Nucleus Neutron Neutral Nucleus Electron Negative Surrounding nucleus Elements An element is one particular type of atom, and it cannot be broken down into a simpler substance by ordinary chemical means Gold Aluminum Helium Atoms & Elements Key Elements In biology, there are SIX very important elements Carbon Hydrogen Oxygen Phosphorus Sulfur Nitrogen How are elements different The number of protons determines the identity of an element Carbon: 6 protons Oxygen: 8 protons The number of electrons determines the property of an element Carbon: 6 electrons, 4 on OUTSIDE Oxygen: 8 electrons, 6 on OUTSIDE Carbon diagrams Chemical Party https://www.youtube.com/watch?v=wBCmt_pJTRA Lonely Atoms Atoms rarely are found alone in nature They will do ANYTHING to get to 8 electrons on the outside Steal Dump Share Compounds A compound is a substance made of atoms of different elements bonded together Result of sharing, stealing, or dumping electrons Atoms bonded in a specific ratio Carbon Compounds (more about this later) Carbon can form many various bonds to form Carbohydrates Proteins Nucleic acids Lipids Ionic Bond Ionic bonds are formed through the electrical force between oppositely charged ions Opposites attract! Ex: Salt aka sodium chloride (NaCl) Positive sodium (Na+) Negative chloride (Cl-) NaCl – ionic bond Ions Ions are atoms that have gained or lost one or more electrons. Results in a change in electrical charge Gain e- becomes negative Lose e- becomes positive Ions, cont. Very important to organisms Hydrogen ions (H+) needed to produce chemical energy in cells Calcium ions (Ca2+) needed for all muscle movement in your body Chloride ions (Cl-) needed for many chemical signals in the brain Covalent Bond Not all atoms easily gain or lose their electrons! Some atoms share their electrons instead! Covalent Bond: forms when atoms share a pair of electrons Usually a very strong bond Atoms may have several covalent bonds to share several electrons H2O – covalent bond CO2 – covalent bond Covalent Bond, cont. Molecule: two or more atoms held together by covalent bonds Ex: carbon dioxide (CO2) Carbon atoms needs 4 electrons to fill outer level, oxygen needs two Carbon shares with 2 oxygen! Ions, Ionic Bonds, & Covalent Bonds Review What are atoms? How are the particles that make up atoms diagrammed? What are the similarities between covalent and ionic bonds? Section 2 Chemical Reactions Objectives Bonds break and form during chemical reactions. Chemical reactions release or absorb energy. Evidence of a chemical reaction Temperature change Formation of a solid (precipitate) Color change (sometimes) Odor (sometimes) Formation of gas Chemical Reaction... Gummy bear torture Bonds break & form during chemical reactions Plant/Animal cells break down sugars to get usable energy Cells build protein molecules by bonding amino acids together Chemical reactions change substances into different substances by breaking and forming chemical bonds Reactants are the substance changed during a chemical reactions Oxygen (O2) & Glucose (C6H12O6) Products are the substances made by a chemical reaction Carbon Dioxide (CO2) & Water (H2O) 6O2 + C6H12O6 6CO2 + 6H2O Reactants & Products Energy Bond energy is the amount of energy that will break a bond between two atoms. Every atom has different bond energy A SPECIFIC amount of energy is needed to break bonds in an oxygen molecule A SPECIFIC amount of energy is needed to break bonds in a glucose molecule Energy is needed to break bonds in molecules is released when bonds are formed The amount of energy released is equal to the energy that breaks the same bond Energy needed to break apart water molecule = energy released when hydrogen & oxygen atoms bond to form a water molecule All chemical reactions involve changes in energy Energy added to the reactants breaks their chemical bonds When new bonds form in the products, energy is released Energy is both absorbed and released during a chemical reaction! Some release more energy than they absorb (Generous) Some absorb more energy than they release (Greedy) Generous chemical RXNs that release more energy than they absorb = Exothermic reaction Excess energy is the difference in bond energy between the reactants and products Excess energy is often released as heat or light Cellular respiration releases usable energy for your cells & heat! Greedy chemical RXNs that absorb more energy than they release = Endothermic reaction In photosynthesis, plants absorb energy from sunlight and use that to make sugars and carbohydrates Exothermic VS. Endothermic graphs But how does a rxn start? Some energy must first be absorbed by the reactants in ANY chemical reaction The amount of energy needed will vary Activation energy is the amount of energy that needs to be absorbed for a chemical reaction to start Push a rock up a hill Activation energy Activation Energy Catalysts & Enzymes A catalyst is a substance that lowers the activation energy needed to start a chemical reaction. Special proteins called enzymes are the biological catalysts that speed up the rate of chemical reactions in biological processes. Enzymes https://www.youtube.com/watch?v=XTUm-75-PL4 Review What are the parts of a chemical reaction? How can energy changes be related to chemical reactions? What is the importance of enzymes in living organisms? Section 3 Water and Solutions Objectives Life depends on hydrogen bonds in water. Many compounds dissolve in water. Some compounds form acids or bases. CELLS •Organisms’ bodies, (their _____________), WATER are made up of mostly ____________________ STRUCTURE •The water in cells gives the cell _______________ TRANSPORTS and ___________________ materials within organisms. •All of the processes necessary for an organism’s life take place within the WATERY ENVIRONMENT of the cell ______________________________ ______________________ 1. HIGH SPECIFIC HEAT ______________________ 2. COHESION ______________________ 3. ADHESION Hydrogen Bonding Negative Charge POLAR •Water is a “______________” molecule •Form when atoms in a molecule UNEQUAL pulls on the have ____________ ELECTRONS _____________ they share. Positive Charge •Opposite charges of polar molecules can HYDROGEN interact to form ____________________ bonds. •An attraction between a slightly POSITIVE _______________ hydrogen atom and a slightly ______________ NEGATIVE atom. (Usually _______________________________) OXYGEN OR NITROGEN •Hydrogen bonds are part of the PROTEINS structures of _______________ and of ______________ DNA Positive Charge Shared Electrons Cohesion: the attraction among __________________ of the same MOLECULES substance. Cohesion from hydrogen bonds makes water molecules _____________________. STICK TOGETHER Cohesion produces __________________, SURFACE TENSION ( “skin on water” ) Adhesion: the attraction among __________________ MOLECULES of ______________ DIFFERENT substances. For example, water molecules stick to other things. Water in a test tube, (water is attracted to the ____________) GLASS Materials such as SUGARS ________________ and ____________ cannot be OXYGEN transported form one part of an organism to another unless they are dissolved in blood, plant sap, or other water based fluids. SOLUTION ______________: Mixture of a substance that is the same throughout. SOLVENT ___________: Substance that is present in the greater amount and dissolves another substance. SOLUTE ___________: Substance that dissolves in a solvent. Mixtures Heterogeneous A mixture with easily separated parts with their distinct properties Homogeneous A mixture that it the SAME throughout and hard to tell individual characteristics ACIDS BASES Some compounds form ______________ or _____________ BREAK UP IONS because they _______________ into _______________ WATER when they dissolve in ___________. BASE: ACID: Compounds that release a proton - a hydrogen ion(H+) – when it dissolves in water Compounds that remove H+ ions from a solution More basic More acidic neutral pH Scale examples Review How does the structure of water make it a good solvent? What are the similarities and differences between solutions and suspensions? What are the differences between acids and bases? Section 4 The Building Blocks of Life Objectives Carbon atoms have unique bonding properties. Four main types of carbon-based molecules are found in living things. PROTEIN ____________________ LIPIDS ____________________ CARBOHYDRATES ____________________ ATP ____________________ NUCLEIC ACID ____________________ Carbohydrates are molecules composed of carbon, hydrogen, and oxygen Include sugars & starches Can be broken down to provide useable energy for cells Major part of plant cell structure The most basic carbs are simple sugars, monosaccharides Polysaccharides are polymers of monosaccharides •USED BY CELLS FOR __________ ENERGY ___________ SOURCE AND __________ ENERGY____________. STORAGE SIMPLE CARBS = _______________________________ ONE OR TWO SUGAR MOLECULES COMPLEX CARBS =LONG _____________________________ CHAINS OF SUGAR MOLECULES _____________________________ Ex) Starches such as potato, ________________________________ pasta, bread ________________________________ Proteins A are the most varied of the carbon-based molecules in organisms Have a role in movement, eyesight, digestion, etc. protein is a polymer made of monomers called amino acids Amino acids are molecules that contain carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur Organisms use 20 different amino acids to build proteins The body makes 12 of the 20, the other 8 come from food CELLS •MAKE UP _________________. LIFE PROCESSES •INVOLVED IN ALL _______ ____________. ACIDS •BUILDING BLOCKS = _________AMINO __________. ENZYME •_________________= TYPE OF PROTEIN THAT STARTS AND SPEEDS UP CHEMICAL REACTIONS IN CELLS. Lipids are nonpolar molecules that include fats, oils, and cholesterol Contain chains of carbon bonded to oxygen & hydrogen Some broken down for useable energy Others are part of a cell’s structure Fatty acids are chains of carbon atoms bonded to hydrogen atoms. Saturated fatty acids have single carbon-carbon bonds Unsaturated fatty acids have double carboncarbon bonds WATER •DON’T MIX WITH ______________. CELL MEMBRANE •PHOSPHOLIPIDS – MAKE UP ________ ______________. STORE___________. ENERGY •FATS AND OILS THAT _________ •ORGANISMS USE FATS AND OILS WHEN THEY HAVE CARBOHYDRATES USED UP ___________________. FATS •_________SOLID AT ROOM TEMPERATURE. OILS •_________LIQUID AT ROOM TEMPERATURE. ENERGY CARRYING •MAJOR ___________ ___________ MOLECULE IN CELL. CARBOHYDRATES AND __________ LIPIDS •ENERGY IN __________________ AND PROTEINS _____________________ MUST BE TRANSFERRED TO ATP IN CELL TO BE USED. Detailed instructions to build proteins are stored in extremely long carbon-based molecules called nucleic acids Nucleic acids are polymers that are made up of monomers called nucleotides Nucleic acids differ from the other carbonbased molecules The others have a large # of functions Nucleic acids have just 1 function… make proteins DNA stores info for putting amino acids together to make proteins RNA helps to build proteins PROTEIN •HAVE ALL INFO NEEDED TO MAKE __________. BLUE PRINT •“_______________” OF LIFE. •BUILDING BLOCKS OF NUCLEOTIDES _____________. DNA RNA •TWO TYPES: ________ AND _______. Each subunit of a complete carbonbased molecule is called a monomer A polymer is a large molecule, or macromolecule, made of many monomers bonded together Monomers of a polymer may be the same (ex. Starches) Or different (proteins) COMPOUND BUILDING BLOCK (POLYMER) (MONOMER) PROTEIN AMINO ACID LIPID (FAT) FATTY ACID CARBOHYDRATE SUGARS NUCLEIC ACIDS NUCLEOTIDE Review What is the role of carbon in living organisms? What are the four major families of biological macromolecules? What are the functions of each group of biological macromolecules?
