Cellular Respiration 1 Cellular Respiration n A catabolic
Cellular Respiration 1
Cellular Respiration n A catabolic, exergonic, oxygen (O 2) requiring process that uses energy extracted from macromolecules (glucose) to produce energy (ATP) and water (H 2 O). C 6 H 12 O 6 + 6 O 2 6 CO 2 + 6 H 2 O + energy glucose ATP 2
Question: n In what kinds organisms does cellular respiration take place? 3
Plants and Animals n n Plants - Autotrophs: Autotrophs self-producers. Animals - Heterotrophs: consumers. 4
Mitochondria n Organelle where cellular respiration takes place. Outer membrane Inner membrane space Matrix Cristae Inner membrane 5
Redox Reaction n n Transfer of one or more electrons from one reactant to another. Two types: 1. Oxidation 2. Reduction 6
Oxidation Reaction n The loss of electrons from a substance. n Or the gain of oxygen Oxidation C 6 H 12 O 6 + 6 O 2 6 CO 2 + 6 H 2 O + energy glucose ATP 7
Reduction Reaction n n The gain of electrons to a substance. Or the loss of oxygen Reduction C 6 H 12 O 6 + 6 O 2 glucose 6 CO 2 + 6 H 2 O + energy ATP 8
Breakdown of Cellular Respiration n Four main parts (reactions). 1. Glycolysis (splitting of sugar) a. cytosol, just outside of mitochondria. 2. Grooming Phase a. migration from cytosol to matrix. 9
Breakdown of Cellular Respiration 3. Krebs Cycle (Citric Acid Cycle) a. mitochondrial matrix 4. Electron Transport Chain (ETC) and Oxidative Phosphorylation a. Also called Chemiosmosis b. inner mitochondrial membrane. 10
1. Glycolysis n n Occurs in the cytosol just outside of mitochondria. Two phases (10 steps): A. Energy investment phase a. Preparatory phase (first 5 steps). B. Energy yielding phase a. Energy payoff phase (second 5 steps). 11
1. Glycolysis A. Energy Investment Phase: Glucose (6 C) 2 ATP 2 ADP + P C-C-C-C 2 ATP - used 0 ATP - produced 0 NADH - produced Glyceraldehyde phosphate (2 - 3 C) (G 3 P or GAP) C-C-C 12
1. Glycolysis B. Energy Yielding Phase Glyceraldehyde phosphate (2 - 3 C) (G 3 P or GAP) 4 ADP + P 4 ATP GAP C-C-C 0 ATP - used 4 ATP - produced 2 NADH - produced Pyruvate (2 - 3 C) (PYR) C-C-C (PYR) 13
1. Glycolysis n Total Net Yield 2 - 3 C-Pyruvate (PYR) 2 - ATP (Substrate-level Phosphorylation) 2 - NADH 14
Substrate-Level Phosphorylation n ATP is formed when an enzyme transfers a phosphate group from a substrate to ADP. Enzyme Example: PEP to PYR Substrate (PEP) Product (Pyruvate) OC=O C-OCH 2 OC=O CH 2 P P P Adenosine ADP P Adenosine ATP 15
Fermentation n Occurs in cytosol when “NO Oxygen” is present (called anaerobic). Remember: glycolysis is part of fermentation Two Types: 1. Alcohol Fermentation 2. Lactic Acid Fermentation 16
Alcohol Fermentation n C C C glucose Plants and Fungi 2 ADP +2 P 2 ATP 2 NADH beer and wine 2 NADH C C C Glycolysis 2 NAD+ 2 Pyruvic acid 2 NAD+ C C 2 Ethanol 2 CO 2 released 17
Alcohol Fermentation n End Products: Alcohol fermentation 2 - ATP (substrate-level phosphorylation) 2 - CO 2 2 - Ethanol’s 18
Lactic Acid Fermentation n Animals (pain in muscle after a workout). C C C Glucose 2 ADP +2 P 2 ATP C C C Glycolysis 2 NAD+ 2 NADH 2 Pyruvic acid 2 NAD+ C C C 2 Lactic acid 19
Lactic Acid Fermentation n End Products: Lactic acid fermentation 2 - ATP (substrate-level phosphorylation) 2 - Lactic Acids 20
2. Grooming Phase n n Occurs when Oxygen is present (aerobic). 2 Pyruvate (3 C) molecules are transported through the mitochondria membrane to the matrix and is converted to 2 Acetyl Co. A (2 C) molecules. Cytosol 2 CO 2 C C C Matrix C-C 2 Pyruvate 2 NAD+ 2 NADH 2 Acetyl Co. A 21
2. Grooming Phase n End Products: grooming phase 2 - NADH 2 - CO 2 2 - Acetyl Co. A (2 C) 22
3. Krebs Cycle (Citric Acid Cycle) n n n Location: mitochondrial matrix. Acetyl Co. A (2 C) bonds to Oxalacetic acid (4 C - OAA) to make Citrate (6 C). It takes 2 turns of the krebs cycle to oxidize 1 glucose molecule. Mitochondrial Matrix 23
3. Krebs Cycle (Citric Acid Cycle) 1 Acetyl Co. A (2 C) OAA (4 C) Citrate (6 C) FADH 2 Krebs Cycle 2 CO 2 (one turn) 3 NAD+ FAD 3 NADH ATP ADP + P 24
3. Krebs Cycle (Citric Acid Cycle) 2 Acetyl Co. A (2 C) Citrate (6 C) OAA (4 C) 2 FADH 2 Krebs Cycle 4 CO 2 (two turns) 6 NAD+ 2 FAD 6 NADH 2 ATP 2 ADP + P 25
3. Krebs Cycle (Citric Acid Cycle) n Total net yield (2 turns of krebs cycle) 1. 2 - ATP (substrate-level phosphorylation) 2. 6 - NADH 3. 2 - FADH 2 4. 4 - CO 2 26
4. Electron Transport Chain (ETC) and Oxidative Phosphorylation (Chemiosmosis) n n n Location: inner mitochondrial membrane. Uses ETC (cytochrome proteins) and ATP Synthase (enzyme) to make ATP. ETC pumps H+ (protons) across innermembrane (lowers p. H in innermembrane space). Inner Mitochondrial Membrane 27
4. Electron Transport Chain (ETC) and Oxidative Phosphorylation (Chemiosmosis) n n The H+ then move via diffusion (Proton Motive Force) through ATP Synthase to make ATP. All NADH and FADH 2 converted to ATP during this stage of cellular respiration Each NADH converts to 3 ATP. Each FADH 2 converts to 2 ATP (enters the ETC at a lower level than NADH). 28
4. Electron Transport Chain (ETC) and Oxidative Phosphorylation (Chemiosmosis) Outer membrane Inner membrane space Matrix Cristae Inner membrane 29
4. ETC and Oxidative Phosphorylation (Chemiosmosis for NADH) higher H+ concentration Intermembrane Space 1 H+ E NADH + H+ 2 H+ 3 H+ T C 2 H+ + 1/2 NAD+ (Proton Pumping) Matrix H+ ATP Synthase Inner Mitochondrial Membrane O 2 H O 2 ADP + P H+ ATP lower H+ concentration 30
4. ETC and Oxidative Phosphorylation (Chemiosmosis for FADH 2) higher H+ concentration Intermembrane Space 1 H+ E T FADH 2 + H+ FAD+ (Proton Pumping) Matrix 2 H+ C 2 H+ + 1/2 O 2 H+ ATP Synthase Inner Mitochondrial Membrane H 2 O ADP + P H+ ATP lower H+ concentration 31
TOTAL ATP YIELD 1. 04 ATP - substrate-level phosphorylation 2. 34 ATP - ETC & oxidative phosphorylation 38 ATP - TOTAL YIELD ATP 32
Eukaryotes (Have Membranes) Total ATP Yield 02 ATP - glycolysis (substrate-level phosphorylation) 04 ATP - converted from 2 NADH - glycolysis 06 ATP - converted from 2 NADH - grooming phase 02 ATP - Krebs cycle (substrate-level phosphorylation) 18 ATP - converted from 6 NADH - Krebs cycle 04 ATP - converted from 2 FADH 2 - Krebs cycle 36 ATP - TOTAL n 33
Maximum ATP Yield for Cellular Respiration (Eukaryotes) Glucose Cytosol Glycolysis 2 Acetyl Co. A 2 Pyruvate Mitochondria Krebs Cycle 2 NADH 2 ATP 6 NADH 2 FADH 2 2 NADH (substrate-level phosphorylation) ETC and Oxidative Phosphorylation 2 ATP (substrate-level phosphorylation) 2 ATP 4 ATP 6 ATP 18 ATP 4 ATP 36 ATP (maximum per glucose) 2 ATP 34
Prokaryotes (Lack Membranes) Total ATP Yield 02 ATP - glycolysis (substrate-level phosphorylation) 06 ATP - converted from 2 NADH - glycolysis 06 ATP - converted from 2 NADH - grooming phase 02 ATP - Krebs cycle (substrate-level phosphorylation) 18 ATP - converted from 6 NADH - Krebs cycle 04 ATP - converted from 2 FADH 2 - Krebs cycle 38 ATP - TOTAL n 35
Question: n In addition to glucose, what other various food molecules are use in Cellular Respiration? 36
Catabolism of Various Food Molecules n Other organic molecules used for fuel. 1. Carbohydrates: polysaccharides 2. Fats: glycerol’s and fatty acids 3. Proteins: amino acids 37
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