Question

In a chloroplast, the highest numbers of protons are found in
A. Stroma
B. Lumen of thylakoids
C. Inter membrane space
D. Antennae complex

Answer 1

Hint: It is a continuous aqueous level surrounded by the membrane thylakoid. It plays a significant role during photosynthesis for photophosphorylation.

Complete Answer:
- Chloroplasts are photosynthesizing organelles where chlorophyll absorbs the energy from the light, converts it and retains it in ATP and NADPH energy storage molecules while releasing oxygen from the water in plant and algal cells.
- The ATP and NADPH are then used for making organic carbon dioxide molecules in a method known as the Calvin cycle. A variety of other functions are accomplished by chloroplasts, including synthesis of fatty acids, synthesis and immune response. Chloroplasts range in number from 1 to 100 per cell.
- The lumen thylakoid is a continuous aqueous level surrounded by the membrane thylakoid. It plays a significant role during photosynthesis for photophosphorylation. Protons are injected through the thylakoid membrane into the lumen during a light-dependent reaction, rendering it acidic to pH 4.
- The ATP synthesis is connected with the production of the proton gradient in the membrane of the thylakoid, according to chemical hypotheses. The separation of the water molecule is performed on the internal side of the membrane and therefore accumulates in the lumen of the thylakoids the ions of hydrogen (proton).

Thus, the correct answer is option B. i.e., Lumen of thylakoids.

Note: The thylakoids are the site for the photosynthesis' light based reactions. These involve the pumping of the protons through the thylakoid membrane in combination with the photosystem electron transport chain and the cytochrome complex, and the ATP synthesis by the ATP synthase, which utilizes the proton gradient.