Transcript The atom
Section 2.1 and 2.2 Living things consist of atoms of different elements Ions form when atoms gain or lose electrons Atoms bonds share pairs of electrons in covalent The atom is the smallest basic unit of matter Atoms are teeny tiny There are three parts of a an atom Subatomic particle Charge Location proton _________ Positive Nucleus neutron _________ electron _________ Neutral Nucleus Electron Surrounding nucleus 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 In biology, there are SIX very important elements carbon ________ Hydrogen oxygen _________ Phosphorus Sulfur nitrogen ________ 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 Atoms rarely are found alone in nature will do ANYTHING to get to 8 electrons on the outside They Steal Dump Share 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 bonds can form many various __________ to form Carbohydrates Proteins Nucleic acids Lipids 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-) Ions are atoms that have gained or lost one or more electrons . Results in a change in electrical charge Gain eLose e- becomes ________________ negative positive becomes ________________ Very important to organisms Hydrogen ions (H+) needed to produce chemical _____________ in cells energy muscle Calcium ions (Ca2+) needed for all _____________ movement in your body Chloride ions (Cl-) needed for many chemical signals in the brain Not all atoms easily gain or lose their electrons! share Some atoms ___________ 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 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! 1. What distinguishes one element from another? 2. Describe the formation of an ionic compound. 3. What is the difference between and ionic bond and a covalent bond? 4. How does a molecule differ from an atom? 5. Explain why a hydrogen atom can become either an ion or a part of a molecule. 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 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 HIGH SPECIFIC HEAT • Hydrogen bonds give water an abnormally ____________________________. RESISTS •Water __________________ changes in temperature because it must _____________ more ____________________ to increase in temperature. Absorb heat energy 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. 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 1. How do polar molecules form hydrogen bonds? 2. What determines whether a compound will dissolve in water? 3. Make a chart that compares acids and bases. 4. How do polar molecules differ from non-polar molecules? How does this difference affect their interactions? 5. Describe an example of cohesion or adhesion that you might observe during your daily life. A detailed look at the process of polymerization polymers from smaller large molecules (_________) ones (__________) monomers Building • Several step process glucose Both are _____________ together enzyme enzyme carries out a reaction between the __________ two monomers This Dehydration ___________: synthesis • ___________ Joins two molecules together by REMOVING _______ water AKA: condensation reaction H2O ________ two REMEMBER, DIMER MEANS ________! The enzyme can carry out numerous dehydration molecule is synthesis reactions until a macro ___________ created EX: ______________ starch Each one of these monomers is glucose ___________ You better believe it! Process hydrolysis called ____________. hydro • “ __________” means water • “ __________” means to split or loosen lysis adding water • This enzyme works by _________ to a polymer General process name: depolymerization turning polymers back into monomers ENZYME H2O What was previous a dimer is now two ______________ again monomers Carbon atoms have unique bonding properties. Four main types of carbon-based molecules are found in living things. PROTEIN ____________________ LIPIDS ____________________ CARBOHYDRATES ____________________ ATP ____________________ NUCLEIC ACID ____________________ Each subunit of a complete carbonbased molecule is called a monomer ______________ polymer _____________ is a large molecule, or macromolecule, made of many monomers bonded together A 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 Carbohydrates are molecules composed of hydrogen carbon, ______________, 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 _______________________ polymers are ______________ of monosaccharides Polysaccharides •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 are the most varied of the carbonbased molecules in organisms Have a role in movement, eyesight, digestion,etc A 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 _______ ____________. AMINO ACIDS •BUILDING BLOCKS = _________ __________. 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 _______. 1. What is the relationship between a polymer and a monomer? 2. Explain how both nucleic acids and proteins are polymers. Be sure to describe the monomers that make up the polymers. 3. How are carbohydrates and lipids similar? How are they different? 4. Explain how the bonding properties of carbon atoms result in the large variety of carbon-based molecules in living things? Chemical Reactions Bonds break and form during chemical reactions. Chemical reactions release or absorb energy. 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 are the substance changed during a chemical reactions Reactants Oxygen (O2) & Glucose (C6H12O6) are the substances made by a chemical reaction Products Carbon Dioxide (CO2) & Water (H2O) 6O2 + C6H12O6 6CO2 + 6H2O Energy is the amount of energy that will break a bond between two atoms. Every atom has different bond energy 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 needed to break bonds in molecules is __________ released is ___________ 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 reversible Many reactions are _________________! The move in both directions at the same time! However many RXNs go from reactants to products until the reactants are all used up Tend to go in one direction depending on the concentrations of the reactants and products They try to balance each other! When a RXN takes place @ equal rate in both directions, the reactant & product concentrations stay the same equilibrium This is called _________________ Equilibrium is reached when both the reactants and products are made at the same rate All chemical reactions involve changes in Energy added to the reactants breaks their chemical bonds When new bonds form in the products, energy is released Energy is both absorbed and chemical reaction! energy released during a 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 Some energy must first be absorbed by the reactants in ANY chemical reaction The amount of energy needed will vary is the amount of energy that needs to be absorbed for a chemical reaction to start Activation energy Push a rock up a hill 1. Hydrogen peroxide (H2O2) breaks down into water (H2O) and oxygen (O2). Explain why this is a chemical reaction. What are the reactants and the products in the reaction? 2. How do endothermic and exothermic reactions differ? 3. What must be true about the bond energies of the reactants and the products of the exothermic process below. Explain. 6O2 + C6H12O6 6CO2 + 6H2O 4. Why might it not always be possible to determine the reactants and the products in a reaction? Explain your answer in terms of chemical equilibrium. Enzymes A catalyst lowers activation energy. Enzymes allow chemical reactions to occur under tightly controlled conditions. To start a chemical RXN, activation energy is necessary The reaction may happen very slowly Reactants may not interact enough, may not be high enough concentration Activation energy & rate of a chemical reaction can be changed by a chemical catalyst decreases A catalyst is a substance that _______________ the activation energy needed to start a reaction rate Also increases the ________ of the reaction Enzymes _____________ are catalysts for reactions in living things Lower the activation energy Increase the rate of the reaction Do not effect chemical equilibrium Does not change the direction of the reaction Almost all enzymes are proteins Depend on their structure to function correctly Conditions such as temperature and pH can affect the function An enzyme’s structure is vital because their shape allows only certain reactants to bind to the enzyme The specific reactants that an enzyme acts on are called substrates Substrates called bind to enzymes at specific places active sites Substrates exactly fit the active sites of enzymes, like a key exactly fits a lock This is why if an enzyme’s structure changes, it may not work 1. How does a catalyst affect the activation energy of a chemical reaction? 2. Describe how the interaction between an enzyme and its substrates changes a chemical reaction. 3. Some organisms live in very hot or very cold acidic environments. Would their enzymes function in a person’s cells? Why or why not? 4. Suppose that the amino acids that make up an enzyme’s active site are changed. How might this change affect the enzyme?