BSC 300 2023 TM_Lecture #10_Cellular Energetics, Part II_In Class Lecture Slides

Provides efficient energy production through oxidative phosphorylation Aerobic metabolism is essential for the survival of complex organisms that require a high energy output.

A series of enzymatic reactions that oxidizes Acetyl CoA to CO2, producing high energy carriers The cycle involves 9 steps and occurs in the mitochondrial matrix.

NAD+ is reduced to NADH + H+ and FAD is reduced to FADH2 These reactions are critical for transferring electrons and generating reducing power.

To produce high energy electron carriers (NADH and FADH2) for ATP synthesis The cycle itself does not produce large quantities of ATP directly.

They can be converted into intermediates of the Citric Acid cycle or Acetyl CoA This allows for flexibility in energy metabolism depending on nutrient availability.

• Electron transfer 2. Chemiosmosis These steps are crucial for the generation of ATP using the proton-motive force.

Net 36 to 38 ATP, depending on the shuttle used for NADH The actual yield can vary based on the efficiency of electron transport and ATP synthesis.

• Flavoproteins (FMN and FAD) • Iron-sulfur proteins (Fe-S) • Heme (Iron Fe2+) • Copper ions (Cu2+) • Ubiquinone (Coenzyme Q) These carriers facilitate the transfer of electrons through the electron transport chain.

Synthesizes ATP using the proton-motive force generated by the electron transport chain It operates through a rotational catalysis mechanism.

Direct transfer of a high-energy phosphate bond to ADP to form ATP This occurs during glycolysis and the Citric Acid cycle.

Indirect energy input into ATP synthesis using the proton gradient established by the electron transport chain This process is essential for high ATP yield from glucose oxidation.

Glucose + 2 ADP + 2 Pi + 2 NAD+ → 2 pyruvate + 2 ATP + 2 NADH + 2 H+ + 2 H2O This equation summarizes the overall conversion of glucose to pyruvate with ATP and NADH production.

Transports cytosolic NADH into the mitochondria, converting it to FADH2 in complex II This shuttle incurs an ATP yield penalty compared to the malate-aspartate shuttle.

Transports cytosolic NADH into the mitochondria, allowing it to enter complex I as NADH This process occurs without additional energy cost and is more efficient.

NADH donates electrons to complex I, while FADH2 donates to complex II This distinction affects the overall ATP yield from each carrier.

The energy stored as a combination of a proton and voltage gradient across a membrane This force drives ATP synthesis and other transport processes in the mitochondria.

• Complex I (NADH Dehydrogenase) • Complex II (Succinate Dehydrogenase) • Complex III (Cytochrome bc1) • Complex IV (Cytochrome oxidase) Each complex has a specific role in electron transport and proton pumping.

Pyruvate is converted into Acetyl CoA, releasing CO2 and producing NADH This step occurs in the mitochondria and serves as the bridge to the Citric Acid cycle.

Inhibits electron transport This regulation is important for maintaining metabolic balance within the cell.