AP Biology Living Metabolism Catabolism Hydrolysis Reaction

AP Biology Living Metabolism

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

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

Energy Coupling Two processes united by Energy

Kinetic Energy vs. Potential Energy

Potential Energy vs. Kinetic Energy

Thermodynamics

LE 8 -3 Heat Chemical energy First law of thermodynamics CO 2 H 2 O Second law of thermodynamics

Δ G = ΔH – TΔ S G- Gibbs “free” energy H – Enthalpy (Total usable energy in the system) T – Temperature in Kelvin (273 + C⁰) S- Entropy (Disorder created by something being broken down) Δ – Change in a variable over time Gibbs “Free” Energy

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

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

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

Potential Energy vs. Kinetic Energy

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

ATP

Phosphorylation

Proteins

R groups of Amino Acids

2’ structure

3’ Structure

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

. Substrate Active site Enzyme-substrate complex

. 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. Substrates Enzyme-substrate complex Active site is available for two new substrate molecules. Enzyme Products are released. Substrates are converted into products. Products Active site (and R groups of its amino acids) can lower EA 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.

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

Optimal Performance

Denaturation of a protein

. A substrate can bind normally to the active site of an enzyme. Substrate Active site Enzyme Normal binding A competitive inhibitor mimics the substrate, competing for the active site. Competitive inhibitor Competitive inhibition 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. Noncompetitive inhibitor Noncompetitive inhibition

Reaction rates for each condition

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

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

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

Energy Coupling Light between energy Photosynthesis and Cellular Respiration ECOSYSTEM Photosynthesis in chloroplasts Organic+ O CO 2 + H 2 O molecules 2 Cellular respiration in mitochondria 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 MITOCHONDRION CYTOSOL NAD+ NADH + H+ Acetyl Co A Pyruvate Transport protein CO 2 Coenzyme A

Actual Kreb’s Cycle

Kreb’s Cycle Simplified

NAD⁺ +2 electrons + H⁺ ion = NADH FAD⁺ + 2 electrons + 2 H⁺ ions = FADH₂ “Making” of electron carriers

Electron Transport Chain is located on the inner FOLDED membrane

Electron Transport Chain (Proteins are H+ Pumps)

“Building” the proton concentration gradient Glycolysis Citric acid cycle ATP Inner mitochondrial membrane Oxidative phosphorylation: electron transport and chemiosmosis ATP H+ H+ H+ Intermembrane space H+ Cyt c Protein complex of electron carriers Q III I II FADH 2 Inner mitochondrial membrane NADH + H+ IV ATP synthase FAD 2 H+ + 1/2 O 2 H 2 O NAD+ Mitochondrial matrix ATP ADP + P i (carrying electrons from food) H+ Electron transport chain Electron transport and pumping of protons (H+), Which create an H+ gradient across the membrane Oxidative phosphorylation Chemiosmosis ATP synthesis powered by the flow of H+ back across the membrane

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

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

Amino Acid Basic Structure a carbon Amino group Carboxyl group

Basic lipid Structure Ester linkage Fat molecule (triacylglycerol)

Negative Feedback