photosynthesis Study Sets and Flashcards | Quizlet
Pigment - Wikipedia
LabBench Activity Plant Pigments and Photosynthesis
In leafy plants, the process of photosynthesis occurs largely in the leaves. Because of this, all the necessary ingredients need to be present in the leaves for the reaction to take place. Carbon dioxide is absorbed into the leaves from the air, water is routed from the roots to the leaves, and sunlight is absorbed into the leaves through chlorophyll. Chlorophyll is a green pigment inside plant cells called chloroplasts - which also have several other structures within them. Chloroplasts are important because they are where photosynthesis takes place.
Many of us are routinely advised by our dermatologists to put on our sunscreen before we go outside and to even add more sunscreen in the middle of the day when the sun’s UV rays are most intense. Wouldn’t it be nice if our bodies could sense how much UV is reaching our skin and then automatically adjust our natural sunscreen protection (in our case the pigment melanin) so as to avoid the negative effects of high UV exposure, such as skin cancer? Well, it seems that many green plants do such a thing on a regular basis. Plants have their own natural UV sunscreens (colorless pigments called flavonoids), which accumulate in their skin (epidermis), and these chemicals filter out much of the detrimental UV before it reaches sensitive photosynthetic tissue inside their leaves (Fig. 1.).
Photosynthesis: Crash Course Biology #8 - YouTube
As we can see, there is a close relationship between the action spectrum and absorption spectrum of photosynthesis. There are many different types of photosynthetic pigments which will absorb light best at different wavelengths. However the most abundant photosynthetic pigment in plants is chlorophyll and therefore the rate of photosynthesis will be the greatest at wavelengths of light best absorbed by chlorophyll (400nm-525nm corresponding to violet-blue light). Very little light is absorbed by chlorophyll at wavelengths of light between 525nm and 625 (green-yellow light) so the rate of photosynthesis will be the least within this range. However, there are other pigments that are able to absorb green-yellow light such as carotene. Even though these are present in small amounts they allow a low rate of photosynthesis to occur at wavelengths of light that chlorophyll cannot absorb.
Some plants and plantlike organisms have developed other pigments to compensate for low light or poor use of light. Cyanobacteria and red algae have phycocyanin and allophycocyanin as accessory pigments to absorbe orange light. They also have a red pigment called phycoerythrin that absorbs green light and extends the range of photosynthesis. The red pigment is found in vegetables. Some red algae are in fact nearly black, so that increases their photosynthetic efficiency. Brown algae have the pigment fucoxanthin in addition to chlorophyll to widen their absorption range. These red and brown algae grow to depths around 270 meters where the light is less than 1% of surface light.
Photosynthesis Quiz - Science Geek
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