Oxidative phosphorylation Oxidative Phosphorylation electron transport chain and

Oxidative phosphorylation • Oxidative Phosphorylation: electron transport chain and chemiosmosis • e- trasport chain embedded in INNER mito membrane • Composed of 3 transmembrane H+ pumps • Electrons flow through e- chain – Loss of energy from e-s powers H+ pump • O 2 is final electron acceptor, no O 2 = no echain

Electron Transport Chain & ATP Synthase

Electron Transport Chain • H+ ions flow back down gradient through ATP synthase • ATP synthase harnesses the proton motive force • ATP synthase adds a P to ADP to make ATP • Do you think the inner mito membrane is permeable to H+ ions? • This is the process of chemiosmosis

Chemiosmosis

Chemiosmosis • Chemiosmosis: an energy-coupling mechanism that uses energy stored in the form of an H+ gradient across a membrane to drive cellular work. • The e- chain and chemiosmosis together make up the process of oxidative phosphorylation – ATP is phosphoralayted – Oxygen is necessary • ATP/Glucose is 36 -38,

ATP Yield / Phase of Respiration

Remember • Aerobic respiration uses oxygn

A few alternatives • When O 2 is not present

Fermentation • Production of ATP w/o O 2 • This is ANAerboic respiration • Glycolysis still in the picture – Rember O 2 not needed for glycolysis – NAD+ is electron acceptor • Two common types… – Alcohol fermentation – Lactic acid fermentation

Alcohol Fermentation • Pyruvate converted to ethanol, releasing CO 2 • NADH is oxidized to make NAD+

Lactic Acid Fermentation • Pyruvate reduced by NADH • So did it gain or loose electrons? • Lactate is formed as waste product.

Facultative Anerobes • Organisms that can do aerobic respiration when possible • Can switch to fermentation under aerobic conditions

Glycolysis and Citric Acid Cycle • Intermediates of these processes can be diverted into a number of other anabolic pathways • Biosynthesis is the production of macromolecules • Many other compounds can be used to make ATP in cellular respiration – Other sugars – Proteins – fats

Try these on for size… • Explain the specific role of glycolysis in cellular respiration. • Describe the function of water in cellular respiration and photosynthesis.