Question

In Engelmann's experiment, bacteria were used to

• A. split light into its spectral components.
• B. detect the sites of O₂ evolution.
• C. absorb the spectra of chlorophyll a and b using Cladophora.
• D. detect the sites of CO₂ evolution and monitor the algal photosynthesis.

Answer 1

Answer: (B)

In his experiment, T.W Engelmann (1843 - 1909) split light into its spectral components using a prism and then illuminated a green alga, Cladophora, placed in a suspension of aerobic bacteria. The bacteria were used to detect the sites of O₂ evolution. He observed that the bacteria accumulated mainly in the region of blue and red light of the split spectrum. A first action spectrum of photosynthesis was thus described. It resembles roughly the absorption spectra of chlorophyll a and b.