Question

question 1
the light - dependent reactions occur in the ______________ and the calvin cycle reactions occur in the ______________.
○ cytoplasm; mitochondria
○ chloroplast membranes; cytoplasm
○ stroma; thylakoid membranes
○ chlorophyll pigments; central vacuoles
○ thylakoid membranes; stroma

Explanation:

The light - dependent reactions of photosynthesis occur in the thylakoid membranes. These reactions use light energy to produce ATP and NADPH. The Calvin cycle (light - independent reactions) occurs in the stroma of the chloroplast. The stroma is the fluid - filled space surrounding the thylakoids.

• Option 1: The cytoplasm is not the site for light - dependent reactions, and mitochondria are involved in cellular respiration, not the Calvin cycle of photosynthesis.
• Option 2: Chloroplast membranes are not the main site for light - dependent reactions (thylakoid membranes are), and the cytoplasm is not the site for the Calvin cycle.
• Option 3: The stroma is for the Calvin cycle, but the light - dependent reactions are in thylakoid membranes, not the other way around.
• Option 4: Chlorophyll pigments are in thylakoid membranes (but the question asks for the location, not just the presence of pigments), and central vacuoles are not related to these reactions.
• Option 5: Thylakoid membranes (for light - dependent reactions) and stroma (for Calvin cycle) is the correct match.

Answer:

E. thylakoid membranes; stroma