Is chlorophyll the only molecule that absorbs light for photosynthesis?

Question

yes or no and why? thank you!

Answer 1

Hello Teresa,

Short answer is no. There are several pigments referred to as accessory pigments that support light capture as part of large structures inside the chloroplast called light-harvesting complexes. In addition to chlorophyll a and chlorophyll b, there are a family of carotenoids involved in light capture in plants.

In red algae, phycoerythrin and phycocyanin are other examples of accessory pigments.

Answer 2

No! There are two types of chlorophyll, a and b, that have similar absorption spectra. Caratenoids also absorb short wavelenghts (as do both types of chlorophyll) but unlike those two pigments, they do not absorb longer wavelenghts. This is why leaves are yellow, orange, and/or red, as caratenoids are the primary pigment present. In addition to helping plants absorb high-energy photons for purpose of photosynthesis, cartenoids also serve as "sun screen" to protect plants from too much sun exposure.

https://www.researchgate.net/profile/Massimiliano_Tattini4/publication/317151195/figure/fig1/AS:498219658760192@1495796231659/Chlorophyll-a-b-and-carotenoids-absorbance-spectra.png