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
• O2 is final electron acceptor, no O2 = 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 O2 is not present
Fermentation
• Production of ATP w/o O2
• This is ANAerboic respiration
• Glycolysis still in the picture
– Rember O2 not needed for glycolysis
– NAD+ is electron acceptor
• Two common types…
– Alcohol fermentation
– Lactic acid fermentation
Alcohol Fermentation
• Pyruvate converted to ethanol, releasing CO2
• 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.