Question

In photosystem-I (PS-I) the pigment molecules absorb maximum light at:

• A. 660 nm
• B. 680 nm
• C. 700 nm
• D. 720 nm

Hint:

PS-I: P700 (700 nm).
PS-II: P680 (680 nm).
Chlorophyll a: 662 nm (red) and 430 nm (blue).

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
This question tests knowledge of photosystems and light absorption.

Step 2: Detailed Explanation:
Photosystem-I (PS-I) absorbs maximum light at 700 nm (C).
The reaction center of PS-I is called P700 (a chlorophyll a molecule).
Photosystem-II (PS-II) absorbs maximum light at 680 nm (P680).
660 nm (A): Absorption by chlorophyll b.
680 nm (B): PS-II reaction center (P680).
720 nm (D): Not a major absorption peak.
Thus, PS-I absorbs maximum at 700 nm.

Step 3: Final Answer:
Thus, PS-I absorbs maximum light at 700 nm, which corresponds to option (C).
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