Question

Which one of the following products diffuses out of the chloroplast during photosynthesis?

• A. ADP
• B. NADPH
• C. \(O_2\)
• D. ATP

Answer 1

The Correct Option is C

Photosynthesis is the process by which green plants, algae, and some bacteria convert light energy, usually from the sun, into chemical energy stored in glucose. This process takes place primarily in the chloroplasts of plant cells.

During photosynthesis, the following key steps occur:

• Light Reactions: These occur in the thylakoid membranes of the chloroplasts. The energy from sunlight is absorbed by chlorophyll and converted into chemical energy in the form of ATP (Adenosine Triphosphate) and NADPH (Nicotinamide Adenine Dinucleotide Phosphate). Additionally, oxygen gas (\(O_2\)) is produced as a byproduct when water molecules are split (photolysis) to provide electrons and protons.
• Calvin Cycle (Dark Reactions): These occur in the stroma of the chloroplasts and do not directly require light. ATP and NADPH produced during the light reactions are used to convert carbon dioxide into glucose.

Now, let us consider which products exit the chloroplast during photosynthesis:

• ADP: ADP is formed when ATP is used to power the Calvin cycle within the chloroplast. It does not need to diffuse out for the purpose of photosynthesis.
• NADPH: This is used within the chloroplast in the Calvin cycle to reduce carbon dioxide. It is not a product that diffuses out during photosynthesis.
• ATP: While ATP is generated in the chloroplast, it is specifically used during the Calvin cycle and does not diffuse out as a product of photosynthesis.
• Oxygen (\(O_2\)): This is produced during the light reactions of photosynthesis as a byproduct of splitting water. It is released from the chloroplast into the atmosphere as a waste product.

Therefore, the correct answer is \(O_2\), as it is the product that diffuses out of the chloroplast during photosynthesis.