Thylakoids removed from chloroplasts were kept in illuminated culture having CO2 and water. It did not produce sugar because of

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  1. absence of enzymes.
  2. non-formation of assimilatory power.
  3. absence of light trapping.
  4. nonliking of photosystem I and photosystem II. 

Answer (Detailed Solution Below)

Option 1 : absence of enzymes.
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Detailed Solution

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The correct answer is the Absence of enzymes
Explanation:
  • Thylakoids are membrane-bound compartments inside chloroplasts that contain chlorophyll and other pigments necessary for the light-dependent reactions of photosynthesis.
  • The light-dependent reactions occurring in the thylakoids produce ATP and NADPH, which are forms of assimilatory power needed for the Calvin cycle (light-independent reactions) to synthesize sugars.
  • The Calvin cycle occurs in the stroma of the chloroplast and requires specific enzymes to convert CO2 and water into glucose.
  • When thylakoids are isolated and placed in an illuminated culture with CO2 and water, the absence of these enzymes in the stroma prevents the synthesis of sugar, even though the thylakoids can still produce ATP and NADPH.
Other Options:
Non-formation of assimilatory power
  • Thylakoids are capable of performing light-dependent reactions to produce ATP and NADPH, which are essential for assimilatory power. Thus, the non-formation of assimilatory power is not the reason for the lack of sugar production.
Absence of light trapping
  • The thylakoids contain chlorophyll and other pigments necessary for capturing light energy. Therefore, light trapping is not absent in isolated thylakoids.
Nonlinking of photosystem I and photosystem II
  • Photosystem I and Photosystem II are both present in the thylakoid membranes and work together to produce ATP and NADPH during the light-dependent reactions. Thus, their nonlinking is not the issue.
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