Question

cellular respiration and photosynthesis are complex, multi - step processes. they both involve a large number of enzyme - catalyzed reactions, multi - protein molecular machines, electron donors, electron acceptors, and electron carriers (which function as both electron donors and acceptors).

classify each reaction sequence or molecular machine as occurring in cellular respiration, photosynthesis, or both.

cellular respiration only
photosynthesis only
both cellular respiration and photosynthesis

photosystems containing the pigment chlorophyll
atp synthase
rubisco
citric acid cycle
a electron transport chain
glycolysis
calvin cycle
pyruvate processing

Explanation:

• Cellular respiration only: Citric acid cycle, glycolysis, pyruvate processing. These are key processes in cellular respiration. The citric acid cycle (Krebs cycle) oxidizes acetyl - CoA. Glycolysis breaks down glucose into pyruvate. Pyruvate processing converts pyruvate into acetyl - CoA for entry into the citric acid cycle.
• Photosynthesis only: Photosystems containing the pigment chlorophyll, rubisco, Calvin cycle. Photosystems (PS I and PS II) with chlorophyll are involved in the light - dependent reactions of photosynthesis. Rubisco (ribulose - 1,5 - bisphosphate carboxylase/oxygenase) is a key enzyme in the Calvin cycle (light - independent reactions) that fixes carbon dioxide.
• Both cellular respiration and photosynthesis: ATP synthase, an electron transport chain. ATP synthase is used in both processes to generate ATP (in the thylakoid membrane during photosynthesis and the inner mitochondrial membrane during cellular respiration). Electron transport chains are present in both (in the thylakoid membrane for photosynthesis and the inner mitochondrial membrane for cellular respiration) and are involved in generating a proton gradient for ATP synthesis.

Answer:

• Cellular respiration only: Citric acid cycle, glycolysis, pyruvate processing.
• Photosynthesis only: Photosystems containing the pigment chlorophyll, rubisco, Calvin cycle.
• Both cellular respiration and photosynthesis: ATP synthase, an electron transport chain.