Question

Phenomenon that describe the first action spectra of photosynthesis:

I. Illumination of Cladophora
II. Detection of O$_2$ release using anaerobic bacteria
III. Accumulation of aerobic bacteria in red and blue light
IV. Cladophora in suspension of anaerobic bacteria

• A. I, II
• B. II, III
• C. III, IV
• D. I, III

Hint:

Engelmann’s experiment = {Cladophora} + aerobic bacteria = action spectrum of photosynthesis.

Answer 1

The Correct Option is D

- In Engelmann’s experiment:
  - A filament of Cladophora was used (I)
  - The aerobic bacteria accumulated in red and blue regions indicating maximum O$_2$ evolution (III)

- II and IV refer to anaerobic studies but are not the key highlights of the original action spectrum experiment.