Cellular Respiration copyright cmassengale 1 Cellular Respiration n

Cellular Respiration copyright cmassengale 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 copyright cmassengale 2

Question: n In what kinds organisms does cellular respiration take place? copyright cmassengale 3

Plants and Animals n n Plants - Autotrophs: Autotrophs self-producers. Animals - Heterotrophs: consumers. copyright cmassengale 4

Mitochondria n Organelle where cellular respiration takes place. Outer membrane Inner membrane space Matrix Cristae Inner membrane copyright cmassengale 5

Redox Reaction n n Transfer of one or more electrons from one reactant to another. Two types: 1. Oxidation 2. Reduction copyright cmassengale 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 copyright cmassengale 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 6 CO 2 + 6 H 2 O + energy glucose ATP copyright cmassengale 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. copyright cmassengale 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. copyright cmassengale 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). copyright cmassengale 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) copyright cmassengale 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 C-C-C (PYR) Pyruvate (2 - 3 C) (PYR) copyright cmassengale 13

1. Glycolysis n Total Net Yield 2 - 3 C-Pyruvate (PYR) 2 - ATP (Substrate-level Phosphorylation) 2 - NADH copyright cmassengale 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 P P P Adenosine ADP OC=O P P C=O CH 2 copyright cmassengale 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 copyright cmassengale 16

Alcohol Fermentation n C C C Plants and Fungi 2 ADP +2 P 2 ATP beer and wine 2 NADH C C C Glycolysis 2 NAD+ 2 NADH 2 Pyruvic acid glucose copyright cmassengale 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 copyright cmassengale 18

Lactic Acid Fermentation n Animals (pain in muscle after a workout). C C C 2 ADP +2 P 2 ATP C C C Glycolysis 2 NAD+ 2 NADH 2 Pyruvic acid Glucose copyright cmassengale 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 copyright cmassengale 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+ copyright cmassengale 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) copyright cmassengale 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 copyright cmassengale 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 + copyright cmassengale 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 copyright cmassengale + 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 copyright cmassengale 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 copyright cmassengale 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). copyright cmassengale 28

4. Electron Transport Chain (ETC) and Oxidative Phosphorylation (Chemiosmosis) Outer membrane Inner membrane space Matrix Cristae Inner membrane copyright cmassengale 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+ H+ ATP Synthase Inner Mitochondrial Membrane O 2 H O 2 ADP + P (Proton Pumping) H+ ATP lower H+ concentration Matrix copyright cmassengale 30

4. ETC and Oxidative Phosphorylation (Chemiosmosis for FADH 2) higher H+ concentration Intermembrane Space 1 H+ E 2 H+ T FADH 2 + H+ FAD+ (Proton Pumping) C 2 H+ + 1/2 O 2 H+ ATP Synthase Inner Mitochondrial Membrane H 2 O ADP + P H+ ATP lower H+ concentration Matrix copyright cmassengale 31

TOTAL ATP YIELD 1. 04 ATP - substrate-level phosphorylation 2. 34 ATP - ETC & oxidative phosphorylation 38 ATP - TOTAL YIELD ATP copyright cmassengale 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 copyright cmassengale 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 cmassengale 36 copyright 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 copyright cmassengale 35

Question: n In addition to glucose, what other various food molecules are use in Cellular Respiration? copyright cmassengale 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 copyright cmassengale 37

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