Metabolism: Energy and Enzymes Chapter 6

LAB Tues 9/13 *next week! Be there! Fri 9/16: Unit test: Ch 2,3, & 6 QOD notebook due Lab: biological science room 136http://www.calstatela.edu/univ/ppa/campus_map.pdf

Biological Science building room 136 -13 on map extra 5 min to get there

QOD Staple/tape is the macromolecule graphic organizer as last QOD What are the 4 shapes of proteins? Draw a small sketch to go with your explanation or each shape

Energy = the ability to do work Kinetic Energy (energy of motion) Potential Energy (stored energy) http://youtube.com/v/Jnj8mc04r9E First Law of Thermodynamics - the law of conservation of energy (not created or destroyed) Second Law of Thermodynamics - energy cannot be changed without a loss of usable energy (heat)

Chemical Reaction Reactants Products Reactants: starting substances, on the left side of the arrow. Products: substances formed during the reaction, on the right side of the arrow. Baking soda + vinegar water + CO2 Reactants Products

What are the reactants and products? 6CO2 + 6H2O C6H12O6 Reactants Products H2O2 H2O + O2 Reactants Products http://www.youtube.com/watch?v=Fz9eV-EWtpY

Reactants --> Products Metabolic Reactions Reactants --> Products  Exothermic - releases energy  Endothermic = absorbs energy

This reaction is exothermic and released heat energy. Chapter 6 Chemistry in Biology This reaction is exothermic and released heat energy. Aka: exergonic The energy of the product is lower than the energy of the reactants.

This reaction is endothermic and absorbed heat energy. Chapter 6 Chemistry in Biology 6.2 Chemical Reactions This reaction is endothermic and absorbed heat energy. Aka: endergonic The energy of the products is higher than the energy of the reactants.

Gibbs free energy change: Energy from exothermic reactions used to drive endothermic rxns

Metabolic Pathways & Enzymes (6-3) Enzyme - protein molecule that functions as an organic catalyst to speed reactions Substrate - reactants in the enzymatic reaction, this is what an enzyme attaches to Activation Energy- the energy required to cause the reaction

activation energy: the minimum amount of energy needed for a reaction. Chemistry in Biology Energy of Reactions activation energy: the minimum amount of energy needed for a reaction. Enzymes lower the activation energy

Enzymes do not affect the Gibbs free energy change, just the activation energy

Properties of Enzymes: Enzymes are made of proteins. They speed up chemical reactions inside the cytoplasm. They are needed only in small amounts They remain unchanged after each reaction and can therefore be reused Each enzyme is specific for a substrate

Substrates: reactants that bind to the enzyme Chapter 6 Chemistry in Biology Substrates: reactants that bind to the enzyme active site: specific location where a substrate binds on an enzyme

Lock and Key Model Each enzyme acts on a specific substrate

Induced Fit Model - substrates and enzymes fit together Induced Fit Model - substrates and enzymes fit together like a lock and key.  Degradation vs Synthesis                  breaking down vs building

Factors Affecting Enzymatic Activity 1. Substrate/ enzyme concentration 2. Temperature & pH * 3. Presence of inhibitors Enzymes can be denatured - they change shape so much that they are no longer effective. High temp or pH can cause denaturation by breaking the H-bonds of the protein 4D structure. 

Siamese cats have an enzyme that works at lower temperatures only, causing the nose and ears to become a darker color than the rest of the body.

Competitive Inhibition vs. Noncompetitive Inhibition (allosteric site) Enzymatic Inhibition - when a substance binds to an enzyme and decreases its activity. (Usually reversible) Competitive Inhibition  vs. Noncompetitive Inhibition (allosteric site) **Both are forms of feedback inhibition Normal Inhibited: competitive Non- competitive http://youtube.com/v/PILzvT3spCQ

Some inhibitors are NOT reversible - poisons like cyanide, lead poisoning all affect enzymes QUESTION: What type of inhibition is pictured below?

Both cofactors and coenzymes help to complete the structure of a conjugated enzyme CO-ENZYME is a small organic non-protein MOLECULE that carries chemical groups between enzymes ex: iron, magnesium or zinc. CO-FACTOR is a non-protein CHEMICAL COMPOUND that is bound tightly to an enzyme and is required for catalysis. ex: NAD+, NADP+ and FAD+

Enzyme Animation (Tutorial)  http://www.stolaf.edu/people/giannini/flashanimat/enzymes/prox-orien.swf Enzyme Quiz http://www.sciencegeek.net/Biology/review/U2Enzymes.htm

Enzyme Lab 2H2O2 ----> 2H2O + O2 Hydrogen Peroxide is broken down by the enzyme catalase within cells.    Potatoes hold the enzyme catalase, which will speed up the breakdown of hydrogen peroxide

Proteins have four shapes 1. Primary Structure - sequence of amino acids that form the polypeptide chain 2. Secondary Structure - Parts of the polypeptide fold into local patterns (alpha helix or pleated sheet) 3. Tertiary Structure - the overall 3D shape (globular or fibrous) 4. Quaternary Structure - consists of two or more polypeptide chains or subunits

Factors Affecting Enzymatic Activity 1. Substrate/ enzyme concentration 2. Temperature & pH * 3. presence of inhibitors Enzymes can be denatured - they change shape so much that they are no longer effective. High temp or pH can cause denaturation. 

The activity of catalase can be seen by the bubbling of oxygen during the reaction Generally speaking, catalase reactions occur faster at warmer temperatures. If temperature is too hot (boiling) then the enzyme becomes denatured

Virtual Labs with Enzymes McGraw Hill Lab Bio 114  Enzymes Lab Bench Enzyme Catalysis

ATP Ribose (sugar) release energy Add energy ADP Diphosphate Energy stored in ATP is released by breaking the bond between the 2nd and 3rd phosphates.

ATP Energy stored in ATP is released by breaking the bond between the 2nd and 3rd phosphates. 2 Phosphate groups P ADP Copyright Pearson Prentice Hall

ATP - the energy currency of cells (adenosine triphosphate) Functions: 1. CHEMICAL WORK - Supplies energy needed to make macromolecules that make up the cell (and organism) 2. TRANSPORT WORK - Supplies energy needed to pump substances across the cell membrane 3. MECHANICAL WORK - supplies energy needed to make muscles contract and other cellular parts to move (flagella)

How do cells make ATP? Cellular respiration Photosynthesis Electron transport chain Chemiosmosis= production of ATP due to hydrogen ion gradient across a membrane

ATP

redox reaction: oxidation-reduction reaction oxidized loses electrons, releasing energy a molecule that is reduced gains electrons, storing energy ADP + P  ATP NAD+ + 2e- + H+  NADP https://www.khanacademy.org/science/biology/cellular-molecular-biology/cellular-respiration/v/oxidation-and-reduction-from-biological-view

Review videos https://www.youtube.com/watch?v=ok9esggzN18 https://www.youtube.com/watch?v=5GMLIMIVUvo

QOD: Enzyme review

FRQ example: An experiment was conducted to measure the reaction rate of the human salivary enzyme α-amylase. Ten mL of a concentrated starch solution and 1.0 mL of α-amylase solution were placed in a test tube. The test tube was inverted several times to mix the solution and then incubated at 25°C. The amount of product (maltose) present was measured every 10 minutes for an hour. The results are given in the table below. (a) Graph the data on the axes provided and calculate the rate of the reaction for the time period 0 to 30 minutes. (b) Explain why a change in the reaction rate was observed after 30 minutes. (c) Draw and label another line on the graph to predict the results if the concentration of α-amylase was doubled. Explain your predicted results. (d) Identify TWO environmental factors that can change the rate of an enzyme-mediated reaction. Discuss how each of those two factors would affect the reaction rate of an enzyme.

FRQ: interpreting graphs FRQ: free response question - there are long and short versions - I have to be able to read your writing - they often ask for interpretation of data FRQ: Interpreting graphs: FRQ: interpreting graphs write at least a sentence per graph, interpreting the data in graph

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