Question

accessory pigments are useful for a)absorbing light energy b) protecting chlorophyll (a) reaction centre from photooxidation c) both a and b d) getting excited​

Answer 1

A light-harvesting system that relied only on the chlorophyll a molecules of the special pair would be rather inefficient for two reasons. First, chlorophyll a molecules absorb light only at specific wavelengths (see Figure 19.6). A large gap is present in the middle of the visible regions between approximately 450 and 650 nm. This gap corresponds to the peak of the solar spectrum, so failure to collect this light would constitute a considerable lost opportunity. Second, even in spectral regions where chlorophyll a absorbs light, many photons would pass through without being absorbed, owing to the relatively low density of chlorophyll a molecules in a reaction center. Accessory pigments, both additional chlorophylls as well as other classes of molecules, are closely associated with reaction centers. These pigments absorb light and funnel the energy to the reaction center for conversion into chemical forms. Indeed, experiments in 1932 by Robert Emerson and William Arnold on Chlorella cells (unicellular green algae) demonstrated that only 1 molecule of O2 was produced for 2500 chlorophyll molecules excited

Answer 2

Answer:

correct answer

c) both a and b

Explanation:

Accessory pigments are light-absorbing compounds, found in photosynthetic organisms, that work in conjunction with chlorophyll a.

They include other forms of this pigment, such as chlorophyll b in green algal and higher plant antennae, while other algae may contain chlorophyll c or d. In addition, there are many non-chlorophyll accessory pigments, such as carotenoids or phycobiliproteins, which also absorb light and transfer that light energy to photosystem chlorophyll.