Biological Pigments

Biological Pigments, also known asbiochromes, are substances found in living organisms that absorb thelightof very specific wavelengths and emit a characteristic electromagnetic signal that allows us to identify them.Color represents the characteristic of electromagnetic radiation falling within the range of 300 to 400 and 700 to 800 nanometers. The specific color of individual chemical substances arises from how they interact with white light.Biochromes play essential roles in diverse biological functions, such as providing tissue coloration, assisting in light absorption for plant photosynthesis, supporting animal vision, and acting as indicators for various physiological processes within organisms.Here, we're going to learn about different biological pigments found in plants for Kerala PSC exams.Types of Biological PigmentsBiological Pigments Found in PlantsBiological pigments serve numerous crucial functions in plants, playing pivotal roles in photosynthesis, protection against environmental stressors, the attraction of pollinators, and signaling developmental stages.1. Chlorophyll:These are the primary pigments responsible for capturing light energy duringphotosynthesis. They absorb light primarily in the blue and red wavelengths while reflecting green light, which gives plants their characteristicgreen color.They are responsible for the green coloring of the plant leaves and parts of the stem in a plant body.The name chlorophyll is derived from two Greek words, Chloros which means green, and phyllon meaning leaf.Chlorophyll molecules are located within organelles known aschloroplasts (grana of the chloroplast), where they convert light energy into chemical energy, producing sugars essential for plant growth and development.There are two types of chlorophylls in green plants. These arechlorophyll a and chlorophyll b.They are considered as the primary photosynthesis pigments.Chlorophyll a produces dark green colours and chlorophyll b produces yellowish green colours. Plants have more chlorophyll a than b.Chlorophyll a is mainly found in algae, cyanobacteria, and all higher plants whereas chlorophyll b is found only in green algae and higher plants.Chlorophyll was first isolated and named by two French men,Joseph Bienaimé CaventouandPierre Joseph Pelletierin 1817.The identification ofmagnesiumin chlorophyll occurred in 1906, marking the initial recognition of this element within living tissue.2. Carotenoids:These pigments are responsible for theyellow, orange, and red huesseen in various plant parts, including fruits, flowers, and leaves.They are found in the chloroplasts and chromoplasts of the plants.Carotenoids serve as accessory pigments in photosynthesis, absorbing light in different wavelengths than chlorophyll. They also act as antioxidants, protecting plant cells from damage caused by excessive light and free radicals.They are water-insoluble and found in the membranes of the cell body. As they are great sources of antioxidants, they promote eye health in humans.There are two main types of carotenoids.CarotenesXanthophyllsCarotenes include pigments like 𝛃-carotene (beta-carotene) and lycopene where as Xanthophylls include pigments like lutein and zeaxanthin. 𝛃-carotene is also known asProvitamin A.3. Flavonoids:Flavones, flavonols, flavanones, etc.: Flavonoids comprise a diverse group of pigments (over 5000 naturally occurring flavonoids) found in plants, contributing to colors ranging from yellow to red.The word Flavonoid is derived from the Latin term flavus meaning yellow.Beyond their role in pigmentation, flavonoids have antioxidant properties, assist in UV protection, and play roles in defense against pathogens.4. Anthocyanins:A type of Flavonoid is responsible for vibrantred,purple, andbluecolors(based on the pH value)in many flowers, fruits, and leaves, anthocyanins are water-soluble pigments.Anthocyanin is derived from two Greek words: Anthos meaning flower and Kyanos meaning blue.They not only attract pollinators but also act as a defense mechanism against UV radiation and herbivores. Additionally, their color intensity can change based on pH levels, serving as indicators of soil acidity.There are additional biological pigments such as Tannins, Betalains, Quinones, and Xanthones. But we're only using general classification here based on the pattern found in the Kerala PSC Question papers.Biological Pigments Found in AnimalsIn the animal world, biochromes often serve as a defense mechanism such as to provide camouflage so that they can blend in the background, signaling, breeding conditions, etc.Major biological pigments found in animals are as follows:MelaninThey are the main pigment found in mammals. Melanin is responsible for the hair color and fur color.They produce colors ranging from black to red eg; the Coloring of the mane of the lion.KeratinIt is a structural protein mainly found in hair, nails, horns, hooves, feathers, etc. They play a major role in cellular activities such as cell growth and protein synthesis.LuciferinSome of the organisms such as fireflies and bacteria exhibit a light-emitting phenomenon called bioluminescence with the help of a biological substance called luciferin.CaroteneThey are found in the chromoplasts of the animals.Different Biological Pigments Found in Animals, Plants & FruitsThe following table is very important for Kerala PSC as many of these items are repeatedly asked in the PSC Question papers:Animals / Plants / FruitsBiological PigmentsApplesFlavonolsGreen ApplesChlorophyllBeetrootBetacyaninBileBilirubin, BiliverdinBloodHaemoglobinBlackberriesAnthocyaninBlueberriesAnthocyaninBrinjalAnthocyaninBroccoliChlorophyllCarrotsCaroteneEgg YolkXanthophyllGrapesAnthocyanin, PolyphenolGuavaLycopeneHairMelaninMeat / MusclesMyoglobinMilkCasein (White, Riboflavin)Carotene (Yellow)OnionsFlavonolsOrangesFlavonones(Hesperidin & Naringenin)Papaya(Red Fleshed)LycopenePurple PotatoesAnthocyaninRed Spinach(ചീര)AnthocyaninRed Cabbage /Violet CabbageAnthocyaninSaffronBixinSkinMelaninTomatoesLycopeneTurmericCurcuminUrineUrochromeWatermelon(Red Fleshed)LycopeneDiseases caused by the lack of Biological PigmentsThere are four main diseases identified by the lack of pigmentation. They areAlbinism: caused due to the partial loss of melanin, hereditary.Leucism: partial loss of pigmentation in animals.Melasma: Dark brown patches appearing on the face.Lamellar Ichthyosis: rare genetic skin condition caused due to the excess production of melanin, fish scale disease.📝SideNotes:Biological Pigments found in Grana of the plants - Chlorophyll a, Chlorophyll b, Carotene & Xanthophyll.Thanks for reading!!!