Cell Respiration Department of Biology, WCU

Metabolism Biochemical reactions Types Anabolism (small to large, e.g. amino acids into proteins) Catabolism (large to small, e.g. digestion, cell respiration)

Cell respiration Energy - ATP (movement, respiration) Adenosine triphosphate (ATP) glucose + O2 CO2 + H2O + ATP Reactions Glycolysis Acetyl CoA Krebs cycle Electron transport chain

Chemical reactions Redox Oxidation (O2 gained or H+ lost) oxidation, reduction Oxidation (O2 gained or H+ lost) C6H12O6 + 6O2 6CO2 + 6H2O + ATP glucose is oxidized to CO2 decrease in energy

Chemical reactions Oxidation reactions

Chemical reactions Reduction reactions O2 lose or H+ gain C6H12O6 + 6O2 6CO2 + 6H2O + ATP glucose is reduced to H2O increase in energy

Chemical reactions Reduction reactions

ATP synthesis Reactions require energy Phosphorylation - energy (protein synthesis, vesicles in Golgi, active transport) Phosphorylation - energy Dephosphorylation

Overview

Overview

Glycolysis Coenzymes NAD - nicatinamide adenine dinucleotide glucose 2 pyruvic acid + 2NADH + 2H+ Coenzymes NAD - nicatinamide adenine dinucleotide FAD - flavin adenine dinucleotide NAD+ - oxidized NADH - reduced

Glycolysis Summary Generated 2 ATP Used glucose, 2NAD+ Produced 2 pyruvic acid Occurs in cytoplasm

Fate of pyruvic acid 1. Anaerobic metabolism Conversion to lactic acid (strenuous exercise) No further ATP produced

Fate of pyruvic acid 2. Aerobic metabolism Conversion to Acetyl CoA (light exercise) Additional ATP produced

Formation of acetyl CoA Summary 1. Decarboxylation carbon removal combines with O2 2. Oxidation removal of H+ combines with NAD+ 3. CoA acetyl group + CoA acetyl CoA

Krebs cycle Summary Use 3 NAD+ Use 1 FAD Produce 2 CO2 Produce 1 ATP per Acetyl CoA

Electron transport chain Summary Series of redox reactions NADH + H+ oxidized to NAD+ One H+ to cristae, one H+ to next carrier protein (reduction) 2 H + + 1/2 O2 = H2O, releases ATP Process is slow

Electron transport chain

ATP Synthesis

Mechanisms of ATP synthesis 1. Substrate level phosphorylation Use of an enzyme

Mechanisms of ATP synthesis 2. Oxidative phosphorylation Energy used to pump H+, energy derived from diffusion gradient