Why is the chlorophyll in plants green or even red, orange, or brown
Green plants absorb light energy using chlorophyll in their leaves. They use it to react carbon dioxide with water to make a sugar called glucose. The glucose is used in respiration, or converted into starch and stored. Oxygen is produced as a by-product.
Plants: Photosynthesis and Chlorophyll - YouTube
The plot of the absorption spectra of the chlorophylls plus correlates well with the observed photosynthetic output. The measure of photochemical efficiency is made by meauring the amount of oxygen produced by leaves following exposure to various wavelengths.
The purpose of photosynthesis is to convert theenergy in photons (the infinitesimally smallpackets of energy that make up light) into thechemical bonds of sugar molecules.
Plants(and animals that eat plants) can then store theenergy and get it back out when they need it bybreaking those chemical bonds. The tricky part ofphotosynthesis is that it takes a very preciseamount of energy to form a particular chemicalbond. Furthermore, the photons from differentcolors of light contain different amounts ofenergy.
You probably know the colors ofthe spectrum (Red, Orange, Yellow, Green, Blue,Indigo, Violet); well, those colors are inascending order of energy -- a photon of bluelight has more energy than a photon of red light(this is true because of Planck's Law, which aphysicist could explain better than I).
Aparticular pigment molecule (like chlorophyll) isspecialized for absorbing a particular color oflight and converting the light energy into theappropriate amount of chemical energy for making achemical bond (actually there are many othermolecules that help the pigment perform thisenergy conversion, but only the pigment itself canabsorb the light). Chlorophyll just absorbs blueand red light; it hardly absorbs any green lightat all, so the green gets reflected back to oureyes, which is why leaves appear green. Otherpigments that plants have in their leaves absorblight of different colors, so they reflect red,orange, yellow, or blue light and appear to bethose colors to our eyes. Because the white lightcoming from the sun is actually made up of photonsof all the different colors, it is veryadvantageous to the plant to have many pigmentsthat can absorb such a wide range of the availablecolors of light.
that are involved in oxygen-producing photosynthesis in plants.
Different photosynthetic organisms use differentcombinations of pigments, which have differentcolors because they absorb and reflect differentfrequencies of light.
Plants and greenalgae (plants are really advanced green algae)contain chlorophyll a (which is teal-green),chlorophyll b (which is yellow-green), andbeta-carotene (which is yellow), thus giving thema green color. Brown algae and their unicellularrelatives (e.g. diatoms) have chlorophylla,chlorophyll c, and lipid pigments calledfucoxanthins,which together give them agolden-brown color. Red algae possess chlorophylla and lipid-based pigments called phycobilins,which give them the brilliant red(or deep blue)color. These different combinations of pigmentsare more or less efficient at collecting light atcertain frequencies and at certain levels of lightintensity (too much will damage the pigment).Thus, they parcel out the Sun's energy to make themost use of it and to not compete with otherphotosynthetic organisms.
In plants and algae, photosynthesis takes place in ..
Plants absorb water through their roots, and carbon dioxide through their leaves. Some glucose is used for respiration, while some is converted into insoluble for storage. The stored starch can later be turned back into glucose and used in respiration. Oxygen is released as a by-product of photosynthesis.
Photosynthesis – Plant Management in Florida Waters
It is evident from these absorption and output plots that only the red and blue ends of the part of the are used by plants in photosynthesis. The reflection and transmission of the middle of the spectrum gives the leaves their green visual color.