Question

Name the accessory pigment of algae.

Answer 1

Algae are a diverse group of marine species that have the ability to perform photosynthesis. Among the algae, three main groups of photosynthetic pigments occur: chlorophylls, carotenoids (carotenes and xanthophylls) and phycobilins.

Complete Answer:
- Pigments are chemical compounds that reflect only certain wavelengths of visible light. This makes them look "colourful." Flowers, corals, and even animal skin contain pigments that give them their colours. The ability of pigments to absorb those wavelengths is more important than their reflection of light.
- Since they communicate with light to absorb only those wavelengths, pigments are useful for plants and other autotrophs — organisms that create their own food using photosynthesis.
- Pigments are the means by which the energy of sunlight is captured for photosynthesis in plants, algae and cyanobacteria. However, because each pigment interacts with only a narrow spectrum, it is typically possible to manufacture multiple types of pigments, each of which has a different colour, to absorb more of the energy of the light.

Accessory pigments are light absorbing compounds found in photosynthetic organisms that function in combination with chlorophyll a. They have other types of this pigment, such as chlorophyll b in green algae and higher plant antennae, while other algae may contain chlorophyll c or d.
- Chlorophylls are greenish pigments that form a ring of porphyrin. It is a stable ring-shaped molecule through which electrons are free to move.
- Since electrons move freely, the ring has the potential to easily gain or lose electrons and therefore the potential to supply energised electrons to other molecules. This is the basic mechanism by which chlorophyll 'captures' the energy of sunlight.
- There are many forms of chlorophyll, the most significant being "a" chlorophyll. This is the molecule that makes photosynthesis possible by transferring its energised electrons onto the molecules that make sugars. Both plants, algae , and cyanobacteria that are photosynthesized contain "a" chlorophyll.The second form of chlorophyll is "b" chlorophyll, which exists only in "green algae" and in plants.

The third type of chlorophyll that is widespread is (not surprisingly) called chlorophyll "c" and is present only in the photosynthetic members of Chromista as well as in the dinoflagellates.
- Carotenoids are typically red, orange , or yellow pigments, and contain the familiar carotene compound that gives the carrots their colour.
- These compounds consist of two small six-carbon rings bound by a "chain" of carbon atoms. As a result, they do not dissolve in water and must be bound to the membranes within the cell.
- Carotenoids can not directly transfer sunlight energy to the photosynthetic pathway, but must convert their absorbed energy to chlorophyll. They are called accessory pigments for this purpose. One very noticeable accessory pigment is fucoxanthin, a brown pigment that stains kelp and other brown algae as well as diatoms.

Note: Pigments are 'molecules which absorb light 's particular wavelengths (energies) and mirror all others.'Pigments are coloured: all the light reflected back at us is the net result of the colour we see.