Cellular Respiration Harvesting Chemical Energy from Organic Molecules

Releasing Energy From Glucose Glucose (6C) 2 X Pyruvate (3C) 2 X Acetyl-CoA (2C) Cytoplasm Mitochondrion Krebs Cycle ATP e - Carriers Electron Transport Chain ½ O 2 H2OH2OH2OH2OATP 2 H + CO 2 CO 2 CO 2 ATP Glycolysis Energy Released e-e-e-e- e-e-e-e- e-e-e-e-

Structure of a Mitochondrion Matrix: Krebs Cycle A Cell One of Its Mitochondria A Crista Inner Membrane: Has Electron Transport Chain Intermembrane Compartment a b c Outer Membrane

Glucose Breakdown Yields Energy C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + energyC 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + energy –40% of released energy captured in ATP Involves two electron carriersInvolves two electron carriers –NAD + + H electrons  NADH –FAD + 2H electrons  FADH 2 –Electrons donated to Electron Transport Chain to produce ATP

Glycolysis 4 ATP 4 ATP 2 NADH 2 NADH 2 ATP 2 ATP 2 NAD + 2 NAD + Set of 10 reactions 2 X Pyruvate (3C) CCCCCC Glucose (6C) CCCCCC Net gain of 2 ATP Occurs in cytoplasm under anaerobic conditions Reverse pathway can convert pyruvate  glucose

Formation of Acetyl CoA CCCCCC CoACoA CCCCCC Pyruvates CoACoA CCCC NAD + NADHNADH C O O C O O Acetyl CoA CCCC Occurs in mitochondrion; Not reversible

Krebs Cycle CCCCC NADH CCCC CoA C CCCCC C O O C O O NAD + NADH NADH ADP ATP H2OH2OH2OH2O FADH 2 FAD H2OH2OH2OH2O CCCC C CCCCC CoA NAD + NADH C O O CCCCC H2OH2OH2OH2O NADH ADP ATP C O O CCCC NADH FADH 2 FAD H2OH2OH2OH2O C CCCCC CCCCC CCCC CoACoA CCCC Acetyl CoA

Krebs Cycle: Summary CoA CC Acetyl-CoA (2C) 2 X Krebs Cycle Set of 7 reactions 6 NAD + 6 NAD + 6 NADH 6 NADH 2 FAD 2 FAD 2 FADH 2 2 FADH 2 2 ADP 2 ADP 2 ATP 2 ATP Electron Transport Chain 4 CO 2 4 CO 2C

Energy Harvested from Glucose (Cytoplasm) Glucose 2 NADH 6 NADH 2 FADH 2 2 Pyruvates 2 CO 2 4 CO 2 2 ATP 4 ATP (Mitochondrial Matrix) (Inner Membrane) 2 ATP 32 ATP Electron Transport System Glycolysis Krebs Cycle Water Oxygen 2 ATP Net Gain

Applying Your Knowledge A.Where is the Krebs cycle located? B.Where does glycolysis occur? C.Where is CO 2 produced? D.Where is the electron transport chain located? 1.Cytoplasm 2.Mitochondrial Matrix 3.Inner Membrane of Mitochondrion 4.Choices 1 and 2 are correct. 5.All of these are correct

ATP is Produced by Chemiosmosis Diffusion of hydrogen ions (H + ) through a differentially permeable membrane, resulting in ATP productionDiffusion of hydrogen ions (H + ) through a differentially permeable membrane, resulting in ATP production –energy from electron transport pumps H + to intermembrane compartment of mitochondrion –H + diffuses to matrix through pores of ATP- synthesizing enzyme –movement of H + provides energy for ATP synthesis

Mitochondrial Chemiosmosis

Mitochondrial Electron Transport System

Without Oxygen, Fermentation Occurs Traffic backed up into mitochondrion

Alcoholic Fermentation for Yeast NAD + CCCCCC Glucose CCC Glycolysis Alcoholic Fermentation NAD + NADH ADPATP ADPATP PyruvatesEthanols CCCCC CC NADH C O O C O O NADHNADH

Lactate Fermentation in Muscles NAD + CCCCCC Glucose CCC CCC Glycolysis Lactate Fermentation NAD + NADH ADPATP ADPATP PyruvatesLactates CCC CCC NADH NADHNADH

Applying Your Knowledge A.Muscle cells produce lactate B.Muscle cells produce ATP C.Yeast cells produce alcohol 1.In the Presence of Oxygen 2.In the Absence of Oxygen 3.Either in the presence or absence of Oxygen 2 3 2

Energy From Macromolecules Glucose (6C) 2 X Pyruvate (3C) 2 X Acetyl-CoA (2C) Krebs Cycle Glycolysis Monosaccharides Complex Carbohydrates Disaccharides

Energy From Macromolecules Glucose (6C) 2 X Pyruvate (3C) 2 X Acetyl-CoA (2C) Krebs Cycle Glycolysis Triglycerides Fatty Acids multiples of 2C Glycerol (~5%)

Energy From Macromolecules Glucose (6C) 2 X Pyruvate (3C) 2 X Acetyl-CoA (2C) Krebs Cycle Glycolysis Proteins Other amino Acids 3C-amino acids

Applying Your Knowledge A.Muscle cells use fats for energy B.Muscle cells use glucose or glycogen for energy 1.In the Presence of Oxygen 2.In the Absence of Oxygen 3.Either in the presence or absence of Oxygen 1 3

Applying Your Knowledge A.Brain cells use glucose for energy B.Brain cells use proteins for energy 1.In the Presence of Carbohydrates 2.In the Absence of Carbohydrates 3.Either in the presence or absence of Carbohydrates 2 3