Search results
Results From The WOW.Com Content Network
Carotenoids serve two key roles in plants and algae: they absorb light energy for use in photosynthesis, and they provide photoprotection via non-photochemical quenching. [4] Carotenoids that contain unsubstituted beta-ionone rings (including β-carotene , α-carotene , β-cryptoxanthin , and γ-carotene ) have vitamin A activity (meaning that ...
Carotenoids containing some oxygen are known as xanthophylls. The two ends of the β-carotene molecule are structurally identical, and are called β-rings. Specifically, the group of nine carbon atoms at each end form a β-ring. The α-carotene molecule has a β-ring at one end; the other end is called an ε-ring. There is no such thing as an ...
The carotenoids have another role as an antioxidant to prevent photo-oxidative damage of chlorophyll molecules. Each antenna complex has between 250 and 400 pigment molecules and the energy they absorb is shuttled by resonance energy transfer to a specialized chlorophyll-protein complex known as the reaction center of each photosystem . [ 1 ]
Their role in supporting photosynthesis is also well documented. [2] [3] Since plants, or microorganisms such algae, fungi and bacteria, have exposure to a much higher day-night, seasonal or other environmental temperature variability than animals, it is not surprising that the level of carotenoids in their tissues is 10 3 – 10 6 higher than ...
Lutein (/ ˈ lj uː t i ɪ n,-t iː n /; [2] from Latin luteus meaning "yellow") is a xanthophyll and one of 600 known naturally occurring carotenoids.Lutein is synthesized only by plants, and like other xanthophylls is found in high quantities in green leafy vegetables such as spinach, kale and yellow carrots.
Two examples of carotenoids are lycopene and β-carotene. These molecules also absorb light most efficiently in the 400 – 500 nm range. Due to their absorption region, carotenoids appear red and yellow and provide most of the red and yellow colours present in fruits and flowers. The carotenoid molecules also serve a safeguarding function.
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. Some of these accessory pigments, in particular the carotenoids, also serve to absorb and dissipate excess light energy, or work as antioxidants. [1]
Carotenoids are the most common group of pigments found in nature. [18] Over 600 different kinds of carotenoids are found in animals, plants, and microorganisms. Marine animals are incapable of making their own carotenoids and thus rely on plants for these pigments. Carotenoproteins are especially common among marine animals.