ATP Production in Eukaryotic Cells

Steps:

• ATP is the cell's energy currency, produced via specific organelle processes.
• Chloroplasts (in plant cells) generate ATP during photosynthesis through photophosphorylation.
• Mitochondria produce ATP in all eukaryotic cells via cellular respiration and oxidative phosphorylation.
• The nucleus stores genetic material but lacks ATP-producing machinery.

Why B is correct:

• Chloroplasts and mitochondria are the primary sites for ATP synthesis, as defined by their roles in light-dependent reactions and the electron transport chain.

Why the others are wrong:

• A includes the nucleus, which transcribes DNA but does not synthesize ATP.
• C omits mitochondria, the main ATP producer in respiration.
• D omits chloroplasts, which produce ATP in photosynthetic organisms.

Final answer: B