Exam 3 Week 1 Notes
Exam 3 Week 1 Notes Biology 111
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This 6 page Class Notes was uploaded by Mallori Wisuri on Tuesday March 1, 2016. The Class Notes belongs to Biology 111 at Ball State University taught by Dr. Metzler in Winter 2016. Since its upload, it has received 19 views.
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Date Created: 03/01/16
Exam 3 Introduction to Metabolism Ch. 8 Energy and Thermodynamics 2/23/2016 *Sole reason why we eat and breath! Vocab need to know! -‐Metabolism: every chemical reaction that goes into your body, breaking down and or building up. Breaking down releases energy and building up requires energy. -‐Anabolism: building things; taking monomer subunits and use the energy released when breaking things down to build new substances. Ex. Anabolic steroids -‐Catabolism: bring in food to ‘break things down’ into their monomer subunits. Does this because your cell wants energy. This is down when bonds are broken because energy is released that the cell can use. Some energy is lost as heat in living organism. Heat is a by-‐product cannot be used in metabolism. -‐Energy -‐Kinetic Energy -‐Potential Energy: energy being stored • Metabolism: is very complex -‐Organized into metabolic pathways -‐Every thing that goes on inside you metabolically is very connected -‐Organize reactions into pathways this is for better control and regulation of what is going on • Biology and Energy -‐Chemical energy in bonds is of most importance -‐Energy stored in bond is potential energy. This energy is sitting there and being stored in the cell. -‐Breaking bonds to release energy so cell can do work -‐Building bonds to store energy to be able to do work later -‐Ex. Lynx and rabbit • Thermodynamics: study of energy transformations -‐Study a system (big or small) that you are studying -‐Closed systems: no interactions between system and environment -‐Open systems: constant exchange between system and environment. Living things are an open system. o First Law of Thermodynamics: energy cannot be created nor destroyed, only transferred and transformed -‐Transformed means to convert from light energy to chemical energy to mechanical energy o Second Law of Thermodynamics: when energy is converted from one form to another; some useable energy is converted to heat. -‐This transformation cannot be perfect/efficient -‐In this transformation you end up with energy in 2 forms. There is useable energy for the system and also unusable energy(heat) that the system cannot use -‐Every energy transformation or transfer increases the entropy of the universe -‐Entropy is the measure of disorder or randomness -‐Universe prefers disorder -‐Living things giving off heat, which makes things moves around more, which is more disordered. Thus leading to more disorder of the universe -‐Ex. Photosynthesis o Entropy: measurement of disorder or randomness of the universe -‐In the equation S represents entropy -‐Want reaction to occur spontaneously must increase entropy -‐Universe likes entropy because it doesn’t cost as much energy(lazy mans out). Universe moves toward entropy. • Biology and Entropy -‐Living things are very ordered -‐Nonliving things we have to maintain and take care of -‐Cell maintains order but taking energy in and gives off heat to increase disorder of everything around us LC: How is it that living things can create all the order and not break laws? -‐Living organisms create order locally, but the energy transformation generates waste heat that increases the entropy of the universe. o Enthalpy: total potential energy of a system -‐ In the equation H represents enthalpy -‐ All the energy something can go after -‐ Thinking of this as bond energy; amount of energy that will come out when you break a bond o Free energy: amount of energy available to do work in a biochemical reaction -‐Energy org has access to, to do work -‐ In the equation G represents free energy -‐ H=G + TS ; G=H -‐ TS -‐ T stands for Temperature -‐ In living systems temperature does NOT have an influences; can maintain a constant temperature. -‐ Entropy influenced by the random motion of molecules, which is controlled by the temperature. -‐ This equation applies to any type of energy transformation • Chemical Reactions and Free Energy -‐Δ???? = Δ???? − ????Δ???? -‐Exergonic: reaction that releases energy; reactants more energy then products; Δ???? is negative. Typical happens when you break a bond. Considered spontaneous. Energetically favorable to the cell because they get energy. -‐Endergonic: reaction puts in energy; reactants less energy then products; Δ???? is positive. Typical happens when you form a bond. Considered nonspontaneous. Energetically unfavorable to the cell because they need energy. LC: If enthalpy is negative and entropy is positive, then the reaction will be… -‐Spontaneous at all temperatures -‐ Δ???? = Δ???? − ????Δ???? -‐ Δ???? = negative − ???? positive -‐ Δ???? = − − + -‐ Δ???? = negative number • Concentrations Matter -‐If you leave reactions alone they are going to try to reach equilibrium; cells don’t want to reach equilibrium. -‐Cells manipulate concentrations to let reactions move in the way they want them -‐Reactants and products -‐Reactions will try to reach equilibrium -‐Cells manipulate concentrations • ATP and Cellular Work -‐Nucleic acid component -‐Pentose sugar, adenine and 3 phosphate groups -‐ATP is the ‘gasoline’ of humans -‐Takes ATP and hydrolyze it. Hydrolysis is when you add a water molecule to break a bond between the 3 and 2 phosphate. This is an exergonic reaction and energy is released. This energy is used to do work. -‐3 types of work: 1. Chemical: this lets your cells link together reactions. We call this reaction coupling. Linking exergonic reaction an endergonic reactions. 2. Transport 3. Mechanical 2/25/2016 Ch. 8 Enzymes • Reaction Coupling: Link exergonic reaction, which is releasing energy and hook it to an end reaction that needs energy. Allowing cell to power this reaction. -‐Convert glutamic acid to glutamine you need to add ammonia to the reaction. This reaction has a positive Δ???? -‐Couples it with hydrolysis of ATP, which has a negative Δ???? -‐This provides energy necessary for ammonia to combine with glutamine -‐Endergonic reactions cannot require more energy then the exergonic reaction gives off. Need to find the overall Δ????! LC: start 13 kcal/mol and got to 28 kcal/mol. Products have more energy then reactants so it is an endergonic reaction. Since its endergonic reaction it is non spontaneous and energetically unfavorable. LC: Which following reactions does NOT need coupled to a second energetically favorable reaction? CORRECT ANSWER Glucose + O2 -‐-‐-‐ CO2 + H20 -‐Breaking glucose down (aerobic respiration) -‐Catabolic WRONG ANSWERS CO2 + H2O -‐-‐-‐glucose + O2 Nucleotides -‐-‐-‐-‐ DNA ADP + P -‐-‐-‐-‐ATP -‐All of these are anabolic and forming bonds • ATP Transport and Mechanical Work -‐Transport work: transporting molecules -‐Mechanical work: flagella/cilia moving • ATP Cycle -‐In catabolizing food energy is being released. Then this energy is used in the cell to phosphorylate ADP to ATP (endergonic-‐bond forming). -‐This ATP that is made is then hydrolyzed to release energy, this energy is used to power reactions -‐ATP is never stored; energy is stored as fat. -‐ATP once made is used *Why does the cell maintain high ATP to ADP ratio? Cell manipulating what is going on, reaction cell wants is to hydrolyze ATP to get energy. Keeps the reaction going in the direction of breaking down ATP to ADP. Vocab need to know! -‐Active site: region on the enzymes where the substrate binds. -‐Substrate: -‐Cofactor: substances that help enzyme work better. Inorganic substances! Ex. Metal ions -‐Coenzyme: substances that help enzyme work better. Organic substances! Ex. Vitamins • Enzymes -‐Biological catalyst: speeds up the rate of the reaction and does NOT cause the reaction to happen -‐Highly specific so an enzyme has only 1 molecule it interacts with -‐Enzymes end in ‘-‐ase’ -‐Tell what an enzyme does by its name Ex. Sucrase is an enzyme that breaks down sucrose -‐Enzyme interacts with its substrates. Substrates bind in the region of the enzyme called an active site. This forms the Enzyme-‐Substrate complex. Enzyme has a subtle conformational change and holds onto the substrate a little tighter. This is called Induced Fit! -‐Enzyme + Substrate-‐-‐-‐ES complex-‐-‐-‐Enzyme + Substrate -‐3D shape of proteins is very important! This is because if enzyme denatures it will lose functionality because the active site will be gone. Then there will be no place for the substrate to bind 1. Substrates enters active site 2. Substrates are held in the active site by weak interactions 3. Active site can lower activation energy and speed up reactions 4. Substrates are converted to products 5. Products are released 6. Active site is now available for two new substrate molecules -‐Enzymes lower Activation energy. Stresses reactants and puts them into their transition state! -‐Enzymes never affect Δ???? only increase the rate of the reaction • Factors affect enzyme activity 1. Concentrations 2. Environmental Factors 3. Cofactors/Coenzymes (SEE VOCAB TO KNOW) 4. Regulation o Concentrations 1. Enzyme concentration vs Rate of reaction graph -‐Add more enzymes over time and if there is a set amount of substrate available the reaction goes up 2. Substrate concentration vs Rate of reaction graph -‐If the enzyme concentration is held steady initially the rate of the reaction goes up and then it reaches a plateau. This is called the saturation effect of the enzyme. Every single active site of an enzyme is occupied! o Environmental Factors 1. Temperature 2. pH -‐Every organism has its own optimal pH and temperature -‐Different compartments in our body with different pH’s -‐Temperature goes down from the optimal temperature then the enzyme activity goes down -‐Temperature goes up from the optimal temperature then the enzyme activity goes down; because the enzymes have denatured -‐Be aware of the environment! o Regulation 1. Control amount of enzyme present -‐Increase production of enzyme -‐Degrade the enzyme 2. Controlling activity of enzyme -‐Feedback inhibition: put things in pathway, each step of pathway is catalyzed by an enzyme. Product will go back and inhibit its own production. Inhibit the enzyme at the beginning of the pathway. -‐Allosteric regulation: does not directly involve anything binding to active site. Molecule can come in bind to the allosteric site, which affects the shape of the enzyme thus affecting the shape of active site.
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