Prokaryotic Cells:
Perform cellular respiration, including the electron transport chain, using their plasma membranes for infolding.
Catabolic Pathway:
Aerobic cellular respiration is catabolic, resulting in a negative free energy change (ΔG) because it releases ATP.
Universal Process:
Occurs in all cells, indicating its essential nature for energy metabolism.
Electron Loss:
When an electron is lost during a reaction, oxidation occurs. "Lose electron = oxidized."
ATP Molecule:
Understanding the structure of ATP is crucial for understanding energy transfer in cells.
Aerobic cellular respiration yields a total of about 32 ATP, combining 28 (from oxidative phosphorylation) and 4 (from glycolysis).
Role of Oxygen:
Oxygen acts as the final electron acceptor in the ETC, which leads to water generation from electrons and hydrogen ions.
Waste Products:
Carbon dioxide (CO2) is a waste product of this process.
Exergonic Reaction:
A negative ΔG signifies that the process is exergonic (releases energy).
Oxidative Phosphorylation:
Collects hydrogen ions through the ETC to generate a significant amount of ATP (28 ATP).
Pyruvate Processing:
Pyruvate is converted into acetyl CoA, which enters the Krebs cycle. Each acetyl CoA allows two turns of the cycle, producing CO2, NADH, and FADH2.
Accumulated NADHs and FADHs contribute to ATP production.
ATP Calculation:
Each NADH produces approximately 2.5 ATP; FADH2 produces 1.5 ATP (due to rounding, some sources list 2 and 2.5).
Phototrophs:
Both protists and plants (as well as some prokaryotes like bacteria) are phototrophs.
CO2, a waste product in respiration, is a key input for photosynthesis, while water, which is also a waste in respiration, is essential for photosynthesis.
Photosynthesis produces glucose, crucial for initiating cellular respiration.