Question

Phycobiliproteins are a complex of accessory pigments and proteins found in cyanobacteria but not in green algae. A researcher claims that the phycobiliprotein pigments in cyanobacteria allow the cyanobacteria to survive in certain aquatic niches better than green algae can.
Which of the following statements best justifies the researcher’s claim?

A. The additional pigments allow the cyanobacteria to store light energy so that it can be used at night to continue photosynthesis.

B. The additional pigments block light and prevent it from reaching photosynthetic organisms at greater depths, so no photosynthetic organisms can live below the surface waters containing cyanobacteria.

C. The additional pigments require energy and cellular resources to produce, so they can be used as an energy source during times of insufficient light.

D. The additional pigments absorb light at wavelengths that green algae cannot absorb; this may allow cyanobacteria to capture more light energy for photosynthesis than green algae can in certain areas.

Answer 1

Answer:

Option D

Explanation:

Cyanobacteria preserve its photosynthetic pigments in the thylakoids which allows masking of green of chlorophyll a and other accessory pigment i.e phycobiliproteins (phycocyanin, allophycocyanin and phycoerythrin).  

Chlorophyll a is mainly responsible for harvesting light for photosynthesis. Phycocyanin is blue in color, allophycocyanin is blue in color  and phycoerythrine is red in color. These together harvest light in the green, yellow and orange part of the spectrum which cannot be used by other phytoplankton species

Hence, option D is correct