Cellular Respiration

Cellular Respiration C6H12O6 + 6O2  6CO2 + 6H2O + energy A catabolic, exergonic, oxygen (O2) requiring process that uses energy extracted from macromolecules (glucose) to produce energy (ATP) and water (H2O). C6H12O6 + 6O2  6CO2 + 6H2O + energy glucose ATP

Question: In what kinds organisms does cellular respiration take place?

Plants and Animals Plants - Autotrophs: self-producers. Animals - Heterotrophs: consumers.

Mitochondria Organelle where cellular respiration takes place. Inner membrane space Matrix Cristae Outer membrane Inner membrane

Redox Reaction Transfer of one or more electrons from one reactant to another. Two types: 1. Oxidation 2. Reduction

Oxidation Reaction Or the gain of oxygen. The loss of electrons from a substance. Or the gain of oxygen. C6H12O6 + 6O2 6CO2 + 6H2O + energy Oxidation glucose ATP

Reduction Reaction The gain of electrons to a substance. Or the loss of oxygen. Reduction glucose ATP C6H12O6 + 6O2  6CO2 + 6H2O + energy

Breakdown of Cellular Respiration Four main parts (reactions). 1. Glycolysis (splitting of sugar) a. cytosol, just outside of mitochondria. 2. Grooming Phase a. migration from cytosol to matrix.

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.

1. Glycolysis 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).

1. Glycolysis A. Energy Investment Phase: C-C-C-C-C-C C-C-C Glucose (6C) Glyceraldehyde phosphate (2 - 3C) (G3P or GAP) 2 ATP - used 0 ATP - produced 0 NADH - produced 2ATP 2ADP + P

1. Glycolysis B. Energy Yielding Phase Glyceraldehyde phosphate (2 - 3C) (G3P or GAP) Pyruvate (2 - 3C) (PYR) 0 ATP - used 4 ATP - produced 2 NADH - produced 4ATP 4ADP + P C-C-C C-C-C GAP (PYR)

1. Glycolysis Total Net Yield 2 - 3C-Pyruvate (PYR) 2 - ATP (Substrate-level Phosphorylation) 2 - NADH

Substrate-Level Phosphorylation ATP is formed when an enzyme transfers a phosphate group from a substrate to ADP. Enzyme Substrate O- C=O C-O- CH2 P Adenosine ADP (PEP) Example: PEP to PYR P ATP O- C=O CH2 Product (Pyruvate) Adenosine

Fermentation 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

Alcohol Fermentation Plants and Fungi  beer and wine 2ATP C P 2NADH C glucose Glycolysis C C C 2 Pyruvic acid 2ATP 2ADP + 2 2NADH P 2 NAD+ C 2 Ethanol 2CO2 released 2NADH 2 NAD+

Alcohol Fermentation End Products: Alcohol fermentation 2 - ATP (substrate-level phosphorylation) 2 - CO2 2 - Ethanol’s

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

Lactic Acid Fermentation End Products: Lactic acid fermentation 2 - ATP (substrate-level phosphorylation) 2 - Lactic Acids

2. Grooming Phase Occurs when Oxygen is present (aerobic). 2 Pyruvate (3C) molecules are transported through the mitochondria membrane to the matrix and is converted to 2 Acetyl CoA (2C) molecules. Cytosol C 2 Pyruvate 2 CO2 2 Acetyl CoA C-C 2NADH 2 NAD+ Matrix

2. Grooming Phase End Products: grooming phase 2 - NADH 2 - CO2 2- Acetyl CoA (2C)

3. Krebs Cycle (Citric Acid Cycle) Location: mitochondrial matrix. Acetyl CoA (2C) bonds to Oxalacetic acid (4C - OAA) to make Citrate (6C). It takes 2 turns of the krebs cycle to oxidize 1 glucose molecule. Mitochondrial Matrix

3. Krebs Cycle (Citric Acid Cycle) 1 Acetyl CoA (2C) 3 NAD+ 3 NADH FAD FADH2 ATP ADP + P (one turn) OAA (4C) Citrate (6C) 2 CO2

3. Krebs Cycle (Citric Acid Cycle) 2 Acetyl CoA (2C) 6 NAD+ 6 NADH 2 FAD 2 FADH2 2 ATP 2 ADP + P (two turns) OAA (4C) Citrate (6C) 4 CO2

3. Krebs Cycle (Citric Acid Cycle) Total net yield (2 turns of krebs cycle) 1. 2 - ATP (substrate-level phosphorylation) 2. 6 - NADH 3. 2 - FADH2 4. 4 - CO2

4. Electron Transport Chain (ETC) and Oxidative Phosphorylation (Chemiosmosis) Location: inner mitochondrial membrane. Uses ETC (cytochrome proteins) and ATP Synthase (enzyme) to make ATP. ETC pumps H+ (protons) across innermembrane (lowers pH in innermembrane space). Inner Mitochondrial Membrane

4. Electron Transport Chain (ETC) and Oxidative Phosphorylation (Chemiosmosis) The H+ then move via diffusion (Proton Motive Force) through ATP Synthase to make ATP. All NADH and FADH2 converted to ATP during this stage of cellular respiration. Each NADH converts to 3 ATP. Each FADH2 converts to 2 ATP (enters the ETC at a lower level than NADH).

4. Electron Transport Chain (ETC) and Oxidative Phosphorylation (Chemiosmosis) Inner membrane space Matrix Cristae Outer membrane Inner membrane

4. ETC and Oxidative Phosphorylation (Chemiosmosis for NADH) ATP Synthase 1H+ 2H+ 3H+ higher H+ concentration H+ ADP + lower H+ (Proton Pumping) P E T C NAD+ 2H+ + 1/2O2 H2O Intermembrane Space Matrix Inner Mitochondrial Membrane

4. ETC and Oxidative Phosphorylation (Chemiosmosis for FADH2) ATP Synthase 1H+ 2H+ higher H+ concentration H+ ADP + lower H+ (Proton Pumping) P E T C FAD+ 2H+ + 1/2O2 H2O Intermembrane Space Matrix Inner Mitochondrial Membrane

Electron Transport Chain Animation

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

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 FADH2 - Krebs cycle 36 ATP - TOTAL

Maximum ATP Yield for Cellular Respiration (Eukaryotes) Glucose Glycolysis 2ATP 4ATP 6ATP 18ATP 4ATP 2ATP 2 ATP (substrate-level phosphorylation) 2NADH 6NADH Krebs Cycle 2FADH2 2 Pyruvate 2 Acetyl CoA ETC and Oxidative Phosphorylation Cytosol Mitochondria 36 ATP (maximum per glucose)

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 FADH2 - Krebs cycle 38 ATP - TOTAL

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

Catabolism of Various Food Molecules Other organic molecules used for fuel. 1. Carbohydrates: polysaccharides 2. Fats: glycerol’s and fatty acids 3. Proteins: amino acids