Question

Different segments of a photosynthetic filamentous alga are exposed to different wavelengths of light as shown below. After a period of time, bacteria known to migrate towards high oxygen concentration, is spread on the surface of the alga. Which region(s) of the alga will have maximum bacterial congregation?

• A. P and R
• B. P and Q
• C. Only P
• D. Only Q

Answer 1

The Correct Option is A

To determine which regions of the photosynthetic filamentous alga will have maximum bacterial congregation, we need to understand the relationship between light wavelength, photosynthesis, and oxygen production.

The bacteria migrate towards high oxygen concentration areas, which are produced in regions where photosynthesis is most active. Photosynthesis in algae is influenced by the availability of light wavelengths that chlorophyll and other pigments absorb effectively.

The key points to note are:

• Chlorophyll absorbs light most effectively in the blue (~400-500 nm) and red (~600-700 nm) regions of the spectrum.
• Region P is exposed to 400 nm light, and Region R is exposed to 600 nm light, both of which are within the optimal absorption range for photosynthesis.
• Region Q, exposed to 500 nm, does not coincide as effectively with the optimal absorption peaks of chlorophyll.

Given these observations, the regions where photosynthesis, and therefore oxygen production, will be maximum are Regions P and R. Consequently, the regions with the maximum bacterial congregation will be Regions P and R.

Conclusion: The correct answer is P and R, where the bacterial congregation will be maximum due to higher oxygen production.