AP Biology AP Biology Living Metabolism

Catabolism (Hydrolysis Reaction) Reactants Energy Products Progress of the reaction Amount of energy released (  G < 0) Free energy Exergonic reaction: energy released

Anabolism (Dehydration Synthesis) Reactants Energy Products Progress of the reaction Amount of energy required (  G > 0) Free energy Endergonic reaction: energy required

Energy Coupling Two processes united by Energy

Kinetic Energy vs. Potential Energy

Potential Energy vs. Kinetic Energy

Thermodynamics

LE 8-3 Chemical energy Heat CO 2 First law of thermodynamicsSecond law of thermodynamics H2OH2O

Gibbs “Free” Energy Δ G = ΔH – TΔ S G- Gibbs “free” energy H – Enthalpy (Total usable energy in the system) T – Temperature in Kelvin (273 + C ⁰ ) S- Entropy (Disorder created by something being broken down) Δ – Change in a variable over time

Unstable (Capable of work) vs. Stable (no work)  G = 0 A closed hydroelectric system  G < 0

LE 8-6a Reactants Energy Products Progress of the reaction Amount of energy released (  G < 0) Free energy Exergonic reaction: energy released

LE 8-6b Reactants Energy Products Progress of the reaction Amount of energy required (  G > 0) Free energy Endergonic reaction: energy required

Potential Energy vs. Kinetic Energy

Types of work performed by living cells NH 2 Glu P i P i P i P i NH 3 P P P ATP ADP Motor protein Mechanical work: ATP phosphorylates motor proteins Protein moved Membrane protein Solute Transport work: ATP phosphorylates transport proteins Solute transported Chemical work: ATP phosphorylates key reactants Reactants: Glutamic acid and ammonia Product (glutamine) made + + +

ATP

Phosphorylation

Proteins

R groups of Amino Acids

2’ structure

3’ Structure

Proteins involved in constructing a red blood cell Quaternary Structure  Chains  Chains Hemoglobin Iron Heme Collagen Polypeptide chain Polypeptide chain

. Substrate Active site Enzyme Enzyme-substrate complex

. Enzyme-substrate complex Substrates Enzyme Products Substrates enter active site; enzyme changes shape so its active site embraces the substrates (induced fit). Substrates held in active site by weak interactions, such as hydrogen bonds and ionic bonds. Active site (and R groups of its amino acids) can lower E A and speed up a reaction by acting as a template for substrate orientation, stressing the substrates and stabilizing the transition state, providing a favorable microenvironment, participating directly in the catalytic reaction. Substrates are converted into products. Products are released. Active site is available for two new substrate molecules.

. Course of reaction without enzyme E A without enzyme  G is unaffected by enzyme Progress of the reaction Free energy E A with enzyme is lower Course of reaction with enzyme Reactants Products

Optimal Performance

Denaturation of a protein

. Substrate Active site Enzyme Competitive inhibitor Normal binding Competitive inhibition Noncompetitive inhibitor Noncompetitive inhibition A substrate can bind normally to the active site of an enzyme. A competitive inhibitor mimics the substrate, competing for the active site. A noncompetitive inhibitor binds to the enzyme away from the active site, altering the conformation of the enzyme so that its active site no longer functions.

Reaction rates for each condition

. Allosteric enzyme with four subunits Regulatory site (one of four) Active form Activator Stabilized active form Active site (one of four) Allosteric activator stabilizes active form. Non- functional active site Inactive form Inhibitor Stabilized inactive form Allosteric inhibitor stabilizes inactive form. Oscillation Allosteric activators and inhibitors

Feedback Inhibition or Negative Feedback Active site available Initial substrate (threonine) Threonine in active site Enzyme 1 (threonine deaminase) Enzyme 2 Intermediate A Isoleucine used up by cell Feedback inhibition Active site of enzyme 1 can’t bind theonine pathway off Isoleucine binds to allosteric site Enzyme 3 Intermediate B Enzyme 4 Intermediate C Enzyme 5 Intermediate D End product (isoleucine)

. Substrate Binding of one substrate molecule to active site of one subunit locks all subunits in active conformation. Cooperativity another type of allosteric activation Stabilized active form Inactive form

Energy Coupling between Photosynthesis and Cellular Respiration ECOSYSTEM Light energy Photosynthesis in chloroplasts Cellular respiration in mitochondria Organic molecules + O 2 CO 2 + H 2 O ATP powers most cellular work Heat energy

Cellular Energy

Process of Cellular Respiration

Glycolysis-cytoplasm 2 ATP activation energy

Energy Investment Phase & Phosphofructokinase

Energy Payoff Phase

Phosphorylation using Free energy

Is Oxygen present?

Pyruvate Conversion CYTOSOL Pyruvate NAD + MITOCHONDRION Transport protein NADH + H + Coenzyme ACO 2 Acetyl Co A

Actual Kreb’s Cycle

Kreb’s Cycle Simplified

“Making” of electron carriers NAD ⁺ +2 electrons + H ⁺ ion = NADH FAD ⁺ + 2 electrons + 2 H ⁺ ions = FADH ₂

Electron Transport Chain is located on the inner FOLDED membrane

Electron Transport Chain (Proteins are H+ Pumps)

“Building” the proton concentration gradient Protein complex of electron carriers H+H+ ATP Glycolysis Oxidative phosphorylation: electron transport and chemiosmosis Citric acid cycle H+H+ Q III I II FAD FADH 2 + H + NADH NAD + (carrying electrons from food) Inner mitochondrial membrane Inner mitochondrial membrane Mitochondrial matrix Intermembrane space H+H+ H+H+ Cyt c IV 2H / 2 O 2 H2OH2O ADP + H+H+ ATP synthase Electron transport chain Electron transport and pumping of protons (H + ), Which create an H + gradient across the membrane P i Chemiosmosis ATP synthesis powered by the flow of H + back across the membrane Oxidative phosphorylation

ATP Synthase Complex using kinetic movement of H+ (protons)

Series of Redox reaction (Electron Transport chain)

Electron Transport Chain is is ALWAYS located on a membrane

Oxygen is at the end

Energy Payoff Phase Need to keep Glycolysis going

Alcohol Fermentation Bacteria and Yeast

Lactic Acid Fermentation Animals such as yourself

Macromolecule Utilization in Cellular Respiration Citric acid cycle Oxidative phosphorylation Proteins NH 3 Amino acids Sugars Carbohydrates Glycolysis Glucose Glyceraldehyde-3- P Pyruvate Acetyl CoA Fatty acids Glycerol Fats

Amino Acid Basic Structure Amino group Carboxyl group  carbon

Basic lipid Structure Ester linkage Fat molecule (triacylglycerol)

Negative Feedback