Question

Electron transport chain mechanism for generation of ATP is carried out in

• A. Outer membrane of Endoplasmic reticulum
• B. Mitochondrial Matrix
• C. Mitochondrial folded inner membrane cristae
• D. In Golgi bodies

Hint:

• Aerobic Respiration Stages in Eukaryotes:
  • Glycolysis: Cytoplasm
  • Pyruvate Oxidation & Krebs Cycle: Mitochondrial matrix
  • Electron Transport Chain & Oxidative Phosphorylation: Inner mitochondrial membrane (cristae)
• The cristae increase surface area for the ETC components and ATP synthase.

Answer 1

The Correct Option is C

The electron transport chain (ETC) and oxidative phosphorylation, which are the primary mechanisms for ATP generation in aerobic cellular respiration, occur in specific locations within the mitochondria in eukaryotic cells.

• Mitochondrial folded inner membrane cristae (Option c): The electron transport chain complexes and ATP synthase (the enzyme that produces ATP) are embedded in the inner mitochondrial membrane. The folds of the inner membrane, called cristae, significantly increase the surface area available for these processes. Protons (H\(^+\)) are pumped from the matrix into the intermembrane space across this inner membrane, creating a proton gradient that drives ATP synthesis. This is the correct location.
• (a) Outer membrane of Endoplasmic reticulum: The ER is involved in protein and lipid synthesis, not primarily ATP generation via ETC.
• (b) Mitochondrial Matrix: The mitochondrial matrix is the site of the Krebs cycle (citric acid cycle) and pyruvate oxidation, which produce NADH and FADH\(_2\) that feed electrons into the ETC. However, the ETC itself is located on the inner membrane, not within the matrix.
• (d) In Golgi bodies: The Golgi apparatus is involved in modifying, sorting, and packaging proteins and lipids for secretion or delivery to other organelles. It is not involved in ATP generation via ETC.

Therefore, the electron transport chain mechanism for ATP generation is carried out in the mitochondrial folded inner membrane (cristae). \[ \boxed{\text{Mitochondrial folded inner membrane cristae}} \]