Presentation on theme: "The Chemistry of Life Chapter 2 Section 2-3 and 2-4"— Presentation transcript:
1 The Chemistry of Life Chapter 2 Section 2-3 and 2-4
2 Carbon Compounds Section 2-3 Demonstration of denaturing proteins – cook an egg; bee sting cure by tenderizer
3 Learning ObjectivesList characteristics of carbohydrates, lipids, nucleic acids and proteinsDescribe basic nucleotide structureExplain the special role of nucleic acids in heredity and cellular controlExplain why molecular structure and shape is crucial to life – it determines how most molecules recognize and respond to each other
5 Protein – Green atoms are carbon Protein above is a computer graphic image. It is an example of a large, complex molecule based on carbon, the green atoms.The Chemistry of Carbon
6 The Chemistry of Carbon Cells are 70-95% water, the rest consists mostly of carbon-based compoundsProteins, DNA, carbohydrates, and othersAll composed of carbon atoms bonded to each other and to atoms of other elementsThese other elements commonly include hydrogen (H), oxygen (O), nitrogen (N), sulfur (S), and phosphorus (P)
7 “Carbon is a girls best friend” Depression is a mental illness that is sometimes treated with lithium.Carbon is recycled naturally on Earth in a cycle called the carbon cycle.A substrate is something that forms a base for something else to be put on.Allotrope is any of the forms that an element may come in.
8 The Chemistry of Carbon Organic chemistryThe study of carbon compounds, focuses on any compound with carbon (organic compounds).The term organic is archaicThough organic compounds implies that these compounds can only come from biological processes, they can be synthesized by non-living reactions
9 The Chemistry of Carbon Organic compoundsAny compound with carbon is said to be organicCO2 to CH4 to proteins and nucleic acids
10 The Chemistry of Carbon History of Organic ChemistryBegan with attempts to purify and improve the yield of products from other organisms.First learned to synthesize simple compounds in the laboratory, butthey had no success with more complex compounds.
11 The Chemistry of Carbon Swedish chemist Berzelius made a distinction between organic compounds that seemed to arise only in living organisms and inorganic compounds from the nonliving world.This led early organic chemists to propose vitalism,the belief in a life outside the limits of physical and chemical laws.
12 The Chemistry of Carbon Support for vitalism began to sink as chemists synthesized more complex organic compounds in the laboratory.Early 1800s, German chemist Friedrich Wöhler synthesized urea in lab from totally inorganic starting materials.
13 The Chemistry of Carbon Herr Doktor Frederich Wöhler
14 The Chemistry of Carbon Milestones in organic chemistry1856 – an attempt to manufacture anti-malarial drug quinine led to accidental discovery of a carbon-based dye, Perkin’s mauve1874 – DDT Dichloro-Diphenyl-Trichloroethane (insecticide properties not discovered until later)1890’s – Aspirin (acetylsalicylic acid) by Bayer AG of Germany
15 The Chemistry of Carbon 1953, Stanley Miller at the University of Chicago was able to simulate chemical conditions on the primitive Earth to demonstrate the spontaneous synthesis of organic compounds.
17 The Chemistry of Carbon Organic chemists finally rejected vitalism and embraced mechanism.all natural phenomena, including the processes of life, are governed by the same physical and chemical laws.
18 The Chemistry of Carbon Organic chemistry was redefined as the study of carbon compounds regardless of origin.Still, organisms produce most organic compounds in an amazing diversity and complexity.However, the same rules apply to inorganic and organic compounds alike.
19 The Chemistry of Carbon Organic chemistryThe term “organic” is an archaic or obsolete term held over from the old days when all chemical compounds were divided into two classes:Inorganic – derived from the nonlivingOrganic – derived from livingFor convenience sake, the terms are still used today.
20 The Chemistry of Carbon Organic chemistry“Organic chemistry is the chemistry of carbon compounds. Biochemistry is the study of carbon compounds that crawl.”Mike Adams
21 The Chemistry of Carbon What is the structure of the carbon atom?With a total of 6 electrons, a carbon atom has 2 in the first shell and 4 in the second shell.
22 The Chemistry of Carbon How does carbon’ s structure relate to its chemical behavior?Like any atom, carbon will tend to form chemical bonds with other atoms to fill up its valence shellLike any atom, carbon valence shell has a maximum capacity of eight electronsTherefore, carbon will tend to form chemical bonds with other atoms to “share” their electrons to fill up its valence shell.
23 The Chemistry of Carbon How does carbon’ s structure relate to its chemical behavior?Carbon usually completes its valence shell by sharing electrons with other atoms in four covalent bonds.This tetravalence by carbon makes large, complex molecules possible.Carbon has little tendency to form ionic bonds by loosing or gaining 4 electrons.
24 The Chemistry of Carbon Carbon’ s structure makes it themost versatile building blocks of molecules.C
25 The Chemistry of Carbon The electron configuration of carbonGives it covalent compatibility with many different elementsHONCHydrogen(valence = 1)Oxygen(valence = 2)Nitrogen(valence = 3)Carbon(valence = 4)
26 The Chemistry of Carbon Inorganic compounds are not based on carbon:A “C” will not be part of their molecular formulaSalts, water, phosphates, sulfates, etc.NaCl, H2SO4, HCl, etcYet organic living things get needed elements in the form of inorganic compounds.
27 The Chemistry of Carbon From one organism to the nextNo real difference in the overall percentages of the major elements of life (C, H, O, N, P, and S).Yet because of carbon, the diversity of molecules is not limited
29 The Chemistry of Carbon Key part of carbon compound diversity is the formation of carbon chainsCarbon atom covalently bonding to carbon atom covalently bonding to carbon atom…Carbon chains form the carbon skeletons of most organic molecules.Vary in length and may be straight, branched, or arranged in closed rings.May also include double bonds.
30 The Chemistry of Carbon Ring StructureCarbon skeletonsDouble bond
33 The Chemistry of Carbon Naming carbon ring structures (just kidding!)
34 MacromoleculesCells join smaller organic molecules together to form larger molecules, known asMacromolecules, may be composed of thousands of atoms and weigh over 100,000 daltons
35 Macromolecules Daltons Dalton is unit of measurement equivalent to atomic mass unitsOne dalton = one atomic mass unit (amu)Periodic table displays the atomic mass of the atoms of the elements in amu
36 MacromoleculesThree of the four classes of macromolecules form chainlike molecules called polymers.Polymers consist of many similar or identical building blocks linked by covalent bonds.The repeated units are small molecules called monomers.Some monomers have other functions of their own.
38 Macromolecules Figure 2-13 When small molecules called monomers join together, they form polymers, or large molecules.
39 MacromoleculesWe shall explore the structure and function of the four major classes of macromolecules which are:CarbohydratesLipidsProteinsNucleic acids
40 Carbohydrates Carbon, hydrogen and oxygen atoms in a 1:2:1 ratio Food molecule – source of energyEnergy is stored when chemical bonds are formed – some bonds store more than othersEnergy released when chemical bonds breakDigestion of carbohydrates, such as pasta and bread, break these bonds are release the energyAlso used as a structural molecule
41 Carbohydrates Each six sided shape is a glucose molecule. Glucose is the monomer - monosaccharide in a starch polymer - polysaccharide
42 CarbohydratesHydrogen bonds between OH groups of carbons 3 and 6
43 Carbohydrates Cellulose is difficult to digest Cows have microbes in their stomachs to facilitate this process
44 Chitin – important structural polysaccharide used in the exoskeletons of arthropods (including insects, spiders, and crustaceans).similar to cellulose, except that it contains a nitrogen-containing appendage on each glucose.Pure chitin is leathery, but the addition of calcium carbonate hardens the chitin.Used to make strong, flexible surgical thread that decomposes after the wound heals.Chitin also forms the structural support for the cell walls of many fungi.
45 Lipids Not generally soluble in water Mostly carbon and hydrogen atoms; also oxygenFats, oils and waxes, plus some steroids (hormones)The job of a lipid is to:Store energyGive structure to cell membranesAs steroids, function as a chemical messenger
47 The three fatty acids in a fat can be the same or different. Fatty acids may vary in length (number of carbons) and in the number and locations of double bonds.If there are no carbon-carbon double bonds, then the molecule is a saturated fatty acid - a hydrogen at every possible position.
48 If there are one or more carbon-carbon double bonds, then the molecule is an unsaturated fatty acid - formed by the removal of hydrogen atoms from the carbon skeleton.Saturated fatty acids are straight chains, but unsaturated fatty acids have a kink wherever there is a double bond.Fig. 5.11b
49 Lipids Fats with saturated fatty acids are saturated fats. Most animal fats are saturated.Saturated fats are solid at room temperature.A diet rich in saturated fats may contribute to cardiovascular disease (atherosclerosis) through plaque deposits.
50 Lipids Fats with unsaturated fatty acids are unsaturated fats. Plant and fish fats, known as oils, are liquid are room temperature.The kinks provided by the double bonds prevent the molecules from packing tightly together.
51 Lipids Major function of fats is energy storage. One gram of fat stores more than twice as much energy as a gram of a polysaccharide.Humans and other mammals store fats as long-term energy reserves in adipose cells.Plants use starch for energy storage when mobility is not a concern but use oils when dispersal and packing is important, as in seeds.
52 Lipids Fat also functions to: Cushion vital organs. Insulate the organism against the environment.This subcutaneous layer is especially thick in whales, seals, and most other marine mammals
53 Nucleic AcidsContain carbon (C), hydrogen (H), oxygen (O), nitrogen (N) and phosphorus (P)Function as the hereditary moleculeTwo formsRNA – ribonucleic acidDNA – deoxyribonucleic acidIndividual monomers are called nucleotides
54 Nucleic Acids Five carbon sugar molecule (gray) Nitrogenous base (green)Phosphate group (blue)Thousands of these monomers may be linked by covalent bonds to create DNA or RNA
55 RNA vs DNA Key difference in structure RNA contains the sugar ribose DNA contains the sugar deoxyriboseDo you see the difference?
58 Nucleic AcidsHow nucleic acids function to store and transmit heredity information will be covered later in the year.
59 Activity Building Model of DNA Double Helix STUDENTActivity Building Model of DNA Double HelixStudents will build a model of the DNA double helix using the Kinex model systemOne of the most spectacular chemistry demonstrations is also one of the simplest. It's the dehydration of sugar (sucrose) with sulfuric acid. Basically, all you do to perform this demonstration is put ordinary table sugar in a glass beaker and stir in some concentrated sulfuric acid (you can dampen the sugar with a small volume of water before adding the sulfuric acid). The sulfuric acid removes water from the sugar in a highly exothermic reaction, releasing heat, steam, and sulfur oxide fumes. Aside from the sulfurous odor, the reaction smells a lot like caramel. The white sugar turns into a black carbonized tube that pushes itself out of the beaker. Here's a nice youtube video for you, if you'd like to see what to expect.
60 Proteins Proteins may Control the rate of chemical reactions Form muscles and boneOthers transport materials in and out of cellsStill others fight disease
61 Proteins Structural proteins – support Storage proteins – storage of amino acidsTransport proteins – transport of other substancesHormonal proteins – coordination of activitiesReceptor proteins – response of cell to chemical stimuli
62 Proteins Contractile proteins – movement Defensive proteins – immune response (antibodies)Enzymatic proteins – selective acceleration of chemical reactions
67 20 different amino acids make up proteins Amino Acid Monomers20 different amino acids make up proteinsOO–HH3N+CCH3CHCH2NHH2CH2NNonpolarGlycine (Gly)Alanine (Ala)Valine (Val)Leucine (Leu)Isoleucine (Ile)Methionine (Met)Phenylalanine (Phe)Tryptophan (Trp)Proline (Pro)H3CS
69 ProteinsThere are 20 amino acid monomers that put together polypeptides.Because the amino acids have different R groups, they can have different chemical properties.Polar vs. nonpolar
70 ProteinsR groups, assembled in a polypeptide, will interact with each other – attracted or repelled.R group interactions determine the polypeptide 3D shape.Protein shape makes protein function possibleShape follows function!
71 ProteinsJust 20 amino acid building blocks? Even that few can create incredible diversity. Just do the math.How many polypeptides 4 amino acids long can be made from 20 amino acids?204 or 20 x 20 x 20 x 20 = 160,000
72 Proteins Amino acids Are linked by covalent peptide bonds OH DESMOSOMESOHCH2CNHOPeptide bondSHSide chainsH2OAmino end (N-terminus)Backbone(a)(b)Carboxyl end (C-terminus)Amino acidsAre linked by covalent peptide bonds
74 Proteins Proteins have four levels of organization Primary – the linear sequence of amino acidsSecondary – the amino acid chain twists and folds upon itselfTertiary – two or more protein chains link to each other by van der Waals weak bondsQuaternary – highest level; two or more tertiary units form weak bonds with each other
75 Four Levels of Protein Structure –Amino acid subunits+H3N Amino endoCarboxyl endcGlyProThrGluSeuLysCysLeuMetValAspAlaArgSerllePheHisAsnTyrTrpLlePrimary structureIs the unique sequence of amino acids in a polypeptide
76 Four Levels of Protein Structure Secondary structureIs the folding or coiling of the polypeptide into a repeating configurationRelies on hydrogen bonds
77 Four Levels of Protein Structure Tertiary structureOverall 3-D shape of a polypeptideResults from interactions between amino acids and R groupsCH2CHO HOCHONH3+-OSCH3H3CHydrophobic interactions and van der Waals interactionsPolypeptide backboneHyrdogen bondIonic bondDisulfide bridge
78 Four Levels of Protein Structure Quaternary structureIs the overall protein structure that results from the aggregation of two or more polypeptide subunitsPolypeptide chainCollagen Chains ChainsHemoglobinIronHeme
79 Summation of the four levels of protein structure.
80 ProteinsWhy is understanding these four levels of organization important?Shape is critical to protein functions!Lose the quaternary level means losing their shape – conformation – which means losing functionNow think of bee sting venom and powered meat tenderizer…
81 MacromoleculesYou will now work together to learn what they are, what they do and how they are built.
82 InstructionsDivide class into 4 person teams with one person for each macromolecule.Position teams in room corners.Each “macromolecule” will complete the worksheet column for their macromolecule.Macromolecules will then meet together; proteins with proteins, nucleic acids with nucleic acids, …These macromolecule groups share information to improve their work.Macromolecule groups will break up and return to original groups.Now all four will share their facts so that everyone completes the worksheet.Completed worksheets are collected (or completed at home).Preparation is completion of reading and chapter notes.Precede activity with PowerPoint review of content.Classes will be divided into eight person teams with two-persons paired for each macromolecule.Position pairs in room thusly, with pairs facing each other across desk:Carbs Nucleic Acids Carbs Nucleic AcidsProteins Lipds Proteins LipidsEach student pair will work together to complete the worksheet column for their macromolecule.Then within each team, the pairs will circulate.Lipids meet with Nucleic Acids and review their column with each other, one to one, recording the information on their own worksheet.Carboydrates meet with Proteins and review their column with each other, one to one, recording the information on their own worksheet.Then the pairs work to fill up the remaining columns.Completed worksheets are collected (or completed at home).
83 SummationList characteristics of carbohydrates, lipids, nucleic acids and proteinsDescribe basic nucleotide structureExplain the special role of nucleic acids in heredity and cellular controlExplain why molecular structure and shape is crucial to life – it determines how most molecules recognize and respond to each other
84 Assignments Read Section 2-3 Complete Chapter 2 Chapter Notes through Section 2-3.Complete the Worksheet Section 2-3 / Due next classRead Section 2-4
85 Cornell Notes Using your Cornell Notes, you will now: compare notes with a partner for one minute.write reflection in bottom space.possible open-notes quiz.Cornell Notes must be turned in on day of chapter test; they will be graded.
86 Cornell Notes Tonight Reread your Cornell Notes in the right column. Review the ideas in the left column.Study your summary/reflection.
88 Learning ObjectivesGiven a chemical reaction, identify the reactants and products, and the coefficients.Distinguish between energy absorbing and energy releasing chemical reactions.Explain the concept of activation energy.
89 Learning ObjectivesExplain why molecular structure and shape is crucial to life – it determines how most molecules recognize and respond to each other.Explain why chemical reactions do not create new matter.Explain the relationship between concentration and the rate of reaction.Explain the importance of enzymes to biochemical reactions.
90 Assignments Complete Chapter 2 Chapter Notes through Section 2-4. Complete the Worksheet Section 2-4 / Due next class
91 Chemical ReactionsChemical property – ability of a substance to undergo a specific chemical changeExample – rust is a chemical reaction between iron and oxygen to create iron oxideComposition of matter always changes
92 Chemical ReactionsNo new matter is created or destroyed during a chemical reactionIf you weighed all the matter of the reactants, and did the same for the products, their masses would be the sameThe number of atoms on both sides would be exactly the sameThe reactions must be “balanced.”
94 Chemical ReactionsSome chemical reactions go to completion; that is, all the reactants are converted to productsMost chemical reactions are reversible,the products in the forward reaction becoming the reactants for the reverse reaction
95 Chemical Reactions Example: 3H2 + N2 <=> 2NH3 Hydrogen and nitrogen molecules combine to form ammonia, but ammonia can decompose to hydrogen and nitrogen moleculesInitially, when reactant concentrations are high, they frequently collide to create productsAs products accumulate, they collide to reform reactants
96 Chemical Reactions How do we know a chemical reaction happened? Clues one can senseChange in colorChange in temperature / heat energyGas productionFormation of a precipitate
97 Demonstration: Chemical Reactions TEACHERPolyurethane FoamRainbow colorsMystery nylon polymer
98 Chemical ReactionsChemical reactions always require the breaking and forming of chemical bonds.Break bonds of reactants.Form new bonds in products.
99 Rust is a chemical reaction – Iron and oxygen reactants combine to form iron oxide product.
100 Photosynthesis: a solar-powered rearrangement of matter – Light energy 6CO2 + 6H2O -> C6H12O6 + 6O2Photosynthesis is an important chemical reaction.Green plants combine carbon dioxide (CO2) from the air and water (H2O) from the soil to create sugar molecules and molecular oxygen (O2), a byproduct.This chemical reaction is powered by sunlight.Humans and other animals depend on photosynthesis for food and oxygen.The overall process of photosynthesis is6CO2 + 6H2O -> C6H12O6 + 6O2This process occurs in a sequence of individual chemical reactions.
101 Energy in Reactions Energy involved in any chemical reactions. Break bonds, release energy.Form bonds, absorb energy.
102 Energy in Reactions Energy Capacity of a physical system to do work. A system can have energy in a variety of forms, for example:kinetic energy due to its motion,potential energy due to the positions of the components,chemical energy stored in chemicals that can undergo a reaction.
103 Energy in Reactions Energy in biochemistry is: stored when chemical bonds are formed.Released when chemical bonds are broken.Though biochemical systems always lost some energy as heat.The trick in biology is to set up systems that recapture, store and release energy in controlled circumstances.
104 Energy in Reactions Certain biochemical processes unleash the energy stored in sugar molecules,recapture it with other molecules, and then use it to (re)build yet more molecules needed by the cell.Organisms take in energy from their surrounding – light energy or chemical energy from food molecules – and then release energy as heat or in waste molecules, such as carbon dioxide.
105 Energy Changes Energy Changes Chemical reactions either release energy or absorb energyReactions releasing energy often occur spontaneously.Reactions absorbing energy do not go until provided with source of energy.
106 The relationship of energy to stability, work capacity, and spontaneous change There is a tendency of all things to seek their lowest state of energy.The molecule at far right has high-energy chemical bonds that are not stable, so it has a tendency to split apart and release that energy.
107 Energy-releasing chemical reaction between hydrogen and oxygen Ignite with a flame or spark, inputting energy.In chemical reactions, chemical bonds are broken and reformed, leading to new arrangements of atoms.The starting molecules in the process are called reactants and the end molecules are called products.In a chemical reaction, all of the atoms in the reactants must be accounted for in the products.The reactions must be “balanced.”For example, we can recombine the covalent bonds of H2 and O2 to form the new bonds of H2O.In this reaction, two molecules of H2 combine with one molecule of O2 to form two molecules of H2O.The ratios of molecules are indicated by coefficients.Some chemical reactions go to completion; that is, all the reactants are converted to products.The amount of energy on the reactant side will equal the amount of energy on the products side (remember some energy always lost as heat energy
108 Energy changes in energy-releasing and energy-absorbing reactions
109 Energy SourcesEnergy is stored in chemical bonds of molecules.
110 Activation EnergyActivation energy – The peak in the curve is the amount of energy required to get the reaction going.Strike at match and you’ll see an example of activation energy.The match starts burning only because another chemical reaction provided the activation energy.
111 Activation EnergyEssential controlling feature of biochemical systems.Life could not exist by relying on spontaneous reactions.Activation energy functions as a control or brake on reactions.Biology links energy-releasing reactions to get the activation energy for energy-absorbing reactions.
112 Demonstration: Decomposition of Sugar TEACHERDemonstration: Decomposition of SugarStudents will observe the decomposition of sugar by a strong acid – a chemical reactionDehydration of water – removal of water from sucrose which is also an exothermic reaction.One of the most spectacular chemistry demonstrations is also one of the simplest. It's the dehydration of sugar (sucrose) with sulfuric acid. Basically, all you do to perform this demonstration is put ordinary table sugar in a glass beaker and stir in some concentrated sulfuric acid (you can dampen the sugar with a small volume of water before adding the sulfuric acid). The sulfuric acid removes water from the sugar in a highly exothermic reaction, releasing heat, steam, and sulfur oxide fumes. Aside from the sulfurous odor, the reaction smells a lot like caramel. The white sugar turns into a black carbonized tube that pushes itself out of the beaker. Here's a nice youtube video for you, if you'd like to see what to expect.
113 Demonstration: Energy Held in Bonds of a Carbohydrate TEACHERDemonstration: Energy Held in Bonds of a CarbohydrateStudents will observe the decomposition of sugar by a strong oxidizer – potassium chlorate – a chemical reactionHighly exothermic requiring we go outside.Chemical bond energy turned into heat energy and light energy.
114 EnzymesSome biochemical reactions just will not work well, or at all, without help.Perhaps their activation energy is too high.Perhaps the reactant concentration is always too low.
115 Enzymes The help comes in the form of a catalyst: Substance that speeds up the rate of a chemical reaction.Are not changed due to the chemical reaction.Catalysts lower a reaction’s activation energy.
116 Enzymes lower a reaction’s activation energy Easier to get the red line reaction going, isn’t it?
118 Enzymes So what is an enzyme exactly? Protein molecules of a very specific shape (conformation).Shape is specific for the reactant(s).Reactant is now called a substrate.
119 EnzymesEnzymes may put two reactants together to form a new molecule, orEnzymes may take a large molecule and break it into smaller molecules. Enzymes capture the reactants, thereby bringing them close together.Enzymes work only when they are at their highest level of organization – quanternary structure.
120 Breaking up isn’t hard to do… Enzyme hexokinase converts the reactants (substates) glucose and ATP into glucose-6-phosphate and ADP
121 Enzyme sucrase breaks down sucrose into two smaller sugars, fructose and glucose
122 Generally speaking… One enzyme for one chemical reaction. So enzyme names come from the reaction is catalyzes.Look for the –ase suffix to recognize an enzyme’s name.Carbonic anhydrase catalyzes reaction that removes water from carbonic acid.
123 Enzymes It’s all about breaking existing bonds and forming new bonds. Enzymes provide a site where reactants can be brought together, thereby reducing activation energy.
124 Enzymes Enzymes are built for specific substrates Specificity comes from ability to form weak bonds between active site and substrateWrong substrate may not be able to form these bondsWeak bonds hold the substrate to the active site
126 Metaphor for the enzyme-substrate complex Enzymes are very specific for substrates, much like a lock is very specific for a key.
127 Regulation of Enzyme Activity Enzymes work if the conditions are right.Enzymes will not work if temperature, pH or other factors disrupt the shape of the enzyme molecule.Denaturation – weak bonds that hold an enzyme together break; loss of shape and function.
128 Regulation of Enzyme Activity Cells also regulate enzymes by using protein messengers that bind to enzymes to turn them off or turn them on.
129 Demonstration: Denaturation TEACHERFry an egg in class.
130 Analyzing Data Read the chart. What do you see? Catalase is an enzyme that helps decompose the toxic hydrogen peroxide that is produced during normal cell activities. (You can use hydrogen peroxide bought from a store as an antiseptic.) The products of this reaction are water and oxygen gas. The pressure of the oxygen gas in a closed container increases as more oxygen is produced. Any increase in the [catalase-hydrogen peroxide] reaction will increase the pressure of oxygen.What variable is plotted on the x-axis? – time in seconds What variable is plotted on the y-axis – pressure of oxygenHow did the rate of reaction change over time in the controlled reaction? – purple line, just before 40 seconds the rate of reaction bottomed out.Suggest an explanation for the change in the control reaction at about 40 seconds. – The catalase/hydrogen peroxide reaction stopped. The simplest explanation is that all the substrate – hydrogen peroxide – was changed into water and oxygen.What effect do acids and bases have on the enzyme catalase? – Acids seem to inhibit the reaction the most, as shown by the little (if any) production of oxygen – the reaction is not happening. Likely the conformation or shape of the enzyme was disrupted by the increases hydrogen ion content. Bases seem to effect the enzyme less so, allowing the reaction to continue to a certain point.Would it be valid to conclude that if a base were added, the rate of the reaction would slow down? - Yes, since even with a base the reaction rate is much lower than the control.Predict what would happen if vinegar were added to a water solution of hydrogen peroxide and catalase. - Acetic acid would slow the reaction down significantly.
131 SummationGiven a chemical reaction, identify the reactants and products, and the coefficients.Distinguish between energy absorbing and energy releasing chemical reactions.Explain the concept of activation energy.
132 SummationExplain why molecular structure and shape is crucial to life – it determines how most molecules recognize and respond to each other.Explain why chemical reactions do not create new matter.Explain the relationship between concentration and the rate of reaction.Explain the importance of enzymes to biochemical reactions.
133 Assignments Complete Chapter 2 Chapter Notes through Section 2-4. Complete Chapter 2 Chapter Review Problems (graded)Complete the Chapter 2 Chapter Notes to endCheck FirstClass for test dates
134 Cornell Notes Using your Cornell Notes, you will now: compare notes with a partner for one minute.write reflection in bottom space.possible open-notes quiz.Cornell Notes must be turned in on day of chapter test; they will be graded.
135 Cornell Notes Tonight Reread your Cornell Notes in the right column. Review the ideas in the left column.Study your summary/reflection.
136 Lab Effect of Temperature on Enzyme Activity STUDENTLab Effect of Temperature on Enzyme ActivityDistribute lab instructions, Tootpick-ase: An Introduction to EnzymesSimulation of how substrate concentration and temperature affect enzyme function.
137 Lab Effect of Temperature on Enzyme Activity STUDENTLab Effect of Temperature on Enzyme ActivityDistribute lab instructions, Effect of Temperature on Enzyme (Catalase) ActivityConduct lab, Effect of Temperature on Enzyme (Catalase) ActivityStudents must read and complete the Pre-Lab activity
138 Lab Conduct lab, Effect of Temperature on Enzyme (Catalase) Activity Students must have read and completed the Pre-Lab activity
139 Test, Chapter 2Following the acid/base lab.Tentative date: