Lecture 2 Outline (Ch. 8, 9) I.Energy II.Thermodynamics III.Metabolism and Chemical Reactions V.Cellular Energy - ATP VI.Enzymes & Regulation VII.Cell Respiration A.Redox Reactions B.Glycolysis C.Coenzyme Junction VII. Preparation for next Lecture

What is Energy? Energy Where does energy on earth come from originally? [equivalent of 40 million billion calories per second!] Types of Energy: - Kinetic Energy = energy of movement - Potential = stored energy

Potential energy can be converted to kinetic energy (& vice versa) Potential Energy Kinetic Energy Energy Thermodynamics – study of energy transformation in a system

Laws of Thermodynamics: Laws of Thermodynamics: Explain the characteristics of energy 1 st Law: Energy is conserved Energy is not created or destroyed Energy can be converted (Chemical  Heat) 2 nd Law: During conversions, amount of useful energy decreases No process is 100% efficient Thermodynamics Energy is converted from more ordered to less ordered forms Entropy (measure of disorder) is increased

Potential vs. Kinetic Energy

Metabolism and Energy Cells convert molecules chemically using cellular energy.

Metabolism Metabolism – chemical conversions in an organism Metabolic reactions: All chemical reactions in organism Anabolic = builds up molecules Two Types of Metabolic Reactions Catabolic = breaks down molecules

Chemical Reaction: Process that makes and breaks chemical bonds + Reactants + Products Two Types of Chemical Reactions: 1) Exergonic = releases energy 2) Endergonic = requires energy Chemical Reactions

Metabolic reactions: Chemical reactions in organism Anabolic = build up Metabolism Two Types of Metabolic Reactions: Catabolic = break down Exergonic = release energy Endergonic = requires energy

Chemical Reactions Exergonic reaction Endergonic reaction -ΔG-ΔG release energy spontaneous +ΔG (or 0) intake energy non-spontaneous Glucose  CO 2 + H 2 0CO 2 + H 2 0  Glucose

Question/Recall: Which has more order? Stores more energy? Polymer or Monomer, Diffused or Concentrated H+? What is relationship between order and energy?

What type of energy is stored in a covalent bond? A.Kinetic energy B.Diffused energy C.Heat energy D.Potential energy E. Conventional energy

Cellular Energy - ATP ATP = adenosine triphosphate ribose, adenine, 3 phosphates last (terminal) phosphate - removable Be able to diagram ATP!

ATP hydrolyzed to ADP Exergonic ATP + H 2 OADP + P i Energy released, used in another reactions (endergonic) Cellular Energy - ATP

ATP regenerated cells power ATP generation by coupling to exergonic reactions Like cellular respiration! Cellular Energy - ATP

ATP Cycle

Making ATP from ADP + P i is… A.Exergonic because it releases energy B.Endergonic because it requires energy C.Exergonic because it requires energy D.Endergonic because it releases energy

Chemical Reactions: Like home offices – tend toward disorder Chemical Reactions Endergonic – energy taken in; Exergonic – energy given off Exergonic Endergonic

Self-Check ReactionExergonic or Endergonic? Breaking down starches to sugars Building proteins Digesting Fats

Activation Energy: Energy required to “jumpstart” a chemical reaction Must overcome repulsion of molecules due to negative charged electrons Nucleus Repel Nucleus Repel Nucleus Activation Energy Activation Energy Chemical Reactions

Exergonic Reaction: –Reactants have more energy than products Activation energy: Make sugar and O 2 molecules collide Chemical Reactions “Downhill” reaction sugar + O 2 water + CO 2

Respiration (ch. 9) preview Cellular Respiration Equation: C 6 H 12 O 6 + O 2  CO 2 + H 2 O You will need to KNOW this equation.

Chemical Reactions and Enzymes Enzymes lower activation energy only for specific reactions cell chooses which reactions proceed! enzymes:cannot make rxns go that wouldn’t otherwise Do speed up rxns that would occur anyway Cannot change endergonic into exergonic rxns

Enzymes Enzymes – control rate of chemical reaction sucrase – enzyme sucrose breakdown sucrase – catalyst-speed up rxn, but not consumed “-ase” enzyme

Enzymes enzyme – specific to substrate active site – part of enzyme -substrate binding tightens fit – induced fit form enzyme-substrate complex catalytic part of enzyme: converts reactant(s) to product(s)

Enzymes substrate(s) enter Enzymes lowers E A by: product(s) formed -template orientation -stress bonds -microenvironment enzyme reused What factors might affect enzyme activity?

Enzymes inhibitors: Drug – blocks HIV enzyme at the active site binds & blocks active site binds allosteric site – alters conformation

If a competitive inhibitor is in an enzyme reaction, can you reverse the inhibition by adding more substrate? A.Yes B.No C.I’m not sure D.Wait, what’s a competitive inhibitor?

Cellular Respiration Overall purpose: convert food to energy animals AND plants complementary to photosynthesis

Cellular Respiration: (Exergonic) Cellular Respiration catabolizes sugars to CO 2 requires O 2 at mitochondrion

Redox Reactions as part of chemical reaction, e- are transferred e- transfer = basis of REDOX reactions (reduction) (oxidation)

Redox Reactions follow the H, e- move with them Use “H rule” for reactions in this class Reactant with more H’s = e donor, will be oxidized Reactant with more O’s = e acceptor, will be reduced ZH 2 + O 2 yields ZO + H 2 O

Self-Check ReactionMolecule Reduced Molecule Oxidized ZH 2 + O 2 yields ZO + H 2 O CH 4 + 2O 2 yields CO 2 + 2H 2 O C 6 H 12 O 6 + O 2 yields CO 2 + H 2 O OxygenZH 2

Redox Reactions Equation for respiration

transfer of e- to oxygen is stepwise Redox Reactions

e- moved by NAD/H (from niacin/vit B 3 ) NADH  carry e- (reduced!) Where do e- come from? NAD+  not carrying e- (oxidized!) Where do e- go? glucose NADH ETC O 2 (makes H 2 O) Redox Reactions

In this equation is NAD+ to NADH oxidized or reduced? A.Reduced, it gained electrons B.Oxidized, it gained electrons C.Reduced, it lost electrons D.Oxidized, it lost electrons NAD + + H + + 2e-  NADH

1. glycolysis Steps of respiration : 2. Citric acid cycle 3. ETC 4. Chemiosmosis Steps of Respiration Coenzyme Junction 4 CO 2 2 CO 2

Stages of respiration: 1. Glycolysis – prep carbons Cellular Respiration

1. Glycolysis 1 glucose (6C)2 pyruvate (3C) Keep track of:- inputs - NAD+/NADH - ATP Cellular Respiration - CO 2 and H 2 O - outputs eukaryotes AND prokaryotes

ATP ADP 1 Glucose Glucose-6-phosphate Glycolysis 2 Glucose-6-phosphate Fructose-6-phosphate

Fructose- 1, 6-bisphosphate Dihydroxyacetone phosphate Glyceraldehyde- 3-phosphate 4 5 Glycolysis ATP ADP

2 2 ADP 2 ATP Phosphoenolpyruvate 2 Pyruvate 10 Glycolysis 2 ATP 2 ADP Step not shown

How many NET ATP are produced by glycolysis? A.one B.two C.four D.six E.eight

-inputs: CO 2 = none yet (2 H 2 O) -outputs: 1 Glucose 2 ATP 4 ATP (2 net) 2 NADH 2 pyruvate Where do the outputs go? Glycolysis Cellular Respiration

Energy production Mitochondria energy from nutrients  ATP

Coenzyme Junction 2 pyruvate (3C) 2 Acetyl CoA (2C) Cellular Respiration pyruvate joins coenzyme A (from vitamin B 5 ) 2 carbons lost (as CO 2 ) 2 NAD+  NADH

Things To Do After Lecture 2… Reading and Preparation: 1.Re-read today’s lecture, highlight all vocabulary you do not understand, and look up terms. 2.Ch. 8 Self-Quiz: #1-6 (correct answers in back of book) 3.Read chapter 9, focus on material covered in lecture (terms, concepts, and figures!) 4.Skim next lecture. “HOMEWORK” (NOT COLLECTED – but things to think about for studying): 1.Describe the relationship between exergonic/endergonic, catabolic/anabolic, and “uphill”/”downhill” chemical reactions 2.Diagram one molecule of ATP and how ADP is different 3.Cut apart the boxes on the previous sheet – match up three (name, energy balance, basic reaction) for glycolysis and three for the coenzyme junction 4.Place the following molecules in order for when they are used/created during glycolysis: fructose-6-phosphate, glucose, glucose-6-phosphate, pyruvate, glyceraldehyde-3-phosphate

Self-check at home Match each Step Name with Energy Balance and Basic Reaction