2Essential Knowledge2.a.1 – All living systems require constant input of free energy ( ).2.a.2 – Organisms capture and store free energy for use in biological processes ( ).
3Cellular Respiration - Preview Def - The process of releasing energy/ATP from foodFood - Stored energy in chemical bonds (provides fuel)ATP - Useable energy for cellular processesWastes – CO2 and H2OMitochondrion store most of equipment needed for rxn
4Respiration (Rs) - Equation C6H12O6 + 6 O CO2 + 6 H2O energy (ATP or heat)Rxn is spontaneous (-∆G)The energy is released (exergonic) from the bonds in the org moleculesRemember: Org molecules store energy in their arrangement of atomsOrg molecules can be carbs, proteins or fats/lipids
6Focus of Chapter Cellular Rs Other Purpose - what is the reaction suppose to do for the cell?Location - where does it occur?Requirements - what is needed to make it run?Products - what does it produce?OtherFermentation, Redox
7Fuel? What is used?Organic molecules with a large amt of hydrogen make great fuel! Why?H becomes oxidized (only has one e-) very easily and energy is releasedRemember: Carbs, fats, proteins are storage bins for e- associated with hydrogen
8Oxidation - definitions Loss of electronsLoss of energyLoss of hydrogens from carbonsEx: Na+ (of NaCl)
9Food and Oxidation Food (organic molecules) contain a lot of H atoms These serve as great long-term fuelsWhy?Because H becomes easily oxidized (releases energy frequently)
10Reduction - definitions Gain of electrons (REDUCING + charge)Gain of energyGain of hydrogens to carbonsEx: O is often reduced!Why?Because electrons are pulled closer to O
12Equation for Rs Oxidized Reduced C6H12O6 + 6 O2 6 CO2 + 6 H2O + energy (ATP/heat) General Redox Equation: Xe- + Y X + Ye-Reduced
13Redox reactions Involves transfer of e- and energy release Sometimes doesn’t involve complete transferRed and Oxd reactions are usually paired or linked together.Why?Because e- transfer requires donor and acceptorMany of the reactions will be done by phosphorylationRedox video
14Phosphorylation Adding a phosphate group to a molecule Two types: Ex: ATP cycle (add P to ADP = ATP)Two types:Oxidative AND substrate-levelThe phosphate group adds “energy” to the molecule for chemical reactions (think ATP cycle)Endergonic rxn
18STEP 1 Glycolysis Glyco- glucose -lysis: to split Formula for glucose: C6H12O6Universal step in all Rs types.Likely the earliest type of cell energy processesOverview:Glucose splits into 2 3-C sugars (then oxidizes to form pyruvate)
19Glycolysis Function - To split glucose and produce NADH and ATP ATP made by substrate-level phosphorylationEnzyme transfers phosphate group from substrate/reactant to ADP to make ATPLocation – Cytoplasm of the cell
24Glycolysis Requirements Glucose2 ATP4 ADP2 NAD+Can occur with or without O2
25Notice: No CO2 made during this step! Glycolysis IntroGlycolysis - Products2 Pyruvic Acids (a 3-Carbon acid)2 ADP, 4 ATP, 2 NADHNET RESULT:2 ATP per glucose2 NADH2 pyruvateH2ONotice: No CO2 made during this step!
27STEP 2 Krebs Cycle Oxidizes fuel from pyruvate molecules Also called: Remember? Pyruvate formed during glycolysisAlso called:Citric Acid CycleTricarboxylic Acid Cycle
28Krebs Cycle Function: Oxidize pyruvic acid (to make CO2 ) Produces: NADH and FADH2Location: Mitochondria matrixBefore Krebs: Acetyl CoA must be formedAcetyl CoA is needed to actually start Krebs
29Pyruvate moved into mito? Why? How?Pyruvate is moved into mitochondria (from cytoplasm)Why? This is where the 2nd step occurs (specific enzymes are in mito)Serves as a checkpointUses active transport and transport proteins.Why? Pyruvate is a charged molecule!
31Krebs Cycle Requirements Pyruvic acid (3C acid)Acetyl coenzyme A4 NAD+1 ADP1 FADDouble this list for each glucose
32LOADS of energy stored in these molecules Krebs Cycle IntroKrebs Cycle Products3 CO2Acetyl CoA4 NADH1 FADH21 ATPDouble this list for each glucoseMade from pyruvateLOADS of energy stored in these molecules
34Krebs Cycle notes Notice: Does NOT require O2 Only 1 ATP made per cycleProduces most of the cell's energy in the form of NADH and FADH2Does NOT require O2
35Comment about ATPThe ATPs produced directly in Krebs Cycle and Glycolysis are by:Substrate-level phosphorylationThe P group is transferred from a substrate to ADPMaking ATP
36At this point…After the Krebs and glycolysis cycles, the cell has made a total of 4 ATP.Remember: some ATP had to be used to power the cycles.Most energy (at this point) comes from NADH and FADH2
37Electron Transport System STEP 3ETC/S or Electron Transport ChainThis is a collection of proteins that are structurally linkedLocated in inner membrane of mitoFolding of mito (cristae) allows for lots of places (large surface area!) for ETC to occur
38ETC/S Uses sets of Cytochromes Fe (Iron)-containing proteins to pass electronsThe Cytochromes alternate between Red and Ox forms and pass electrons down to O2Remember: LEO, GER; LEO the lion goes GERLosing Electrons is Oxidation; Gaining Electrons is Reduction
46ATP Synthase Enzyme An enzyme that uses the flow of H+ to make ATP Works like an ion pump in reverse, or like a waterwheel under the flow of H+ “water”Power source:H+ concentration difference on opposite sides of mitochondrial membrane
47Oxidative Phosphorylation ATP synthase uses oxidative phosphorylation to make ATP during ETCUses H ions to make ATP and water (using Oxygen)
54Lactic Acid Fermentation Done by human muscle cells under oxygen debtLactic Acid is a toxin and can cause soreness and stiffness in musclesOxygen intake can’t keep up with sugar breakdownUsed in dairy industry (yogurt/cheese)Also used to produce methanol and acetone
55Fermentation - Summary Way of using up NADH so Glycolysis can still runProvides ATP to a cell even when O2 is absent
69Summary Identify the basic chemical equation for cellular respiration. Identify the main reaction sequences of cellular respiration.Recognize the location, function, requirements, and products, for each cellular respiration reaction.Recognize and be able to discuss the chemiosmotic model for ATP generation.Recognize the reactions and importance of fermentation.Contrast and compare aerobic and anaerobic respiration.Identify the biological and commercial importances of respiration.
70Exclusion StatementsYou do NOT need to memorize the steps in glycolysis and the Krebs cycle, the structures of the molecules, or the names of the enzymes that are involved.You do NOT need to memorize the names of the specific electron carriers in the electron transport chain (ETC).