Emphasis Heading 1 Exercise 4 Questions: What is the pattern of absorption of th
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Emphasis Heading 1 Exercise 4 Questions: What is the pattern of absorption of the different pigments at different wavelengths of light? How does wavelength influence absorption for different pigments? Hypothesis: Results: Fill out the table below with the wavelengths corresponding to the peak and valley of absorption for each pigment Table 3. Summary of the wavelength ranges that were maximally and minimally PigmentP Predicted absorptionWavelemgth(s) of peaks (nm) Wavelengtho) of Maximum abserption Mimimum absorption (nm) Chlorophyll A 430 nm Chlorophyll B 450 m Xanthophyll435 nm420 nm 420 nm 720 nm 460 nm 700,720 nm 680,700,720,580 nm Beta carotene 450 mm 460 nm 640,660,680,700,720 nm 30 4 5 6 7 8 9 0Explanation / Answer
If you've ever stayed out too long in the sun and gotten a sunburn, you're probably well aware of the sun's immense energy. Unfortunately, the human body can't make much use of solar energy, aside from producing a little Vitamin D (a vitamin synthesized in the skin in the presence of sunlight).
Plants, on the other hand, are experts at capturing light energy and using it to make sugars through a process called photosynthesis. This process begins with the absorption of light by specialized organic molecules, called pigments, that are found in the chloroplasts of plant cells. Here, we’ll consider light as a form of energy, and we'll also see how pigments – such as the chlorophylls that make plants green – absorb that energy.
Pigments absorb light used in photosynthesis
In photosynthesis, the sun’s energy is converted to chemical energy by photosynthetic organisms. However, the various wavelengths in sunlight are not all used equally in photosynthesis. Instead, photosynthetic organisms contain light-absorbing molecules called pigments that absorb only specific wavelengths of visible light, while reflecting others.
The set of wavelengths absorbed by a pigment is its absorption spectrum. In the diagram below, you can see the absorption spectra of three key pigments in photosynthesis: chlorophyll a, chlorophyll b, and ?-carotene. The set of wavelengths that a pigment doesn't absorb are reflected, and the reflected light is what we see as color. For instance, plants appear green to us because they contain many chlorophyll a and bmolecules, which reflect green light.
Since different colors have different wavelengths, wavelengths of red, blue and green lights are all different.
Light Energy and Pigments
Light Energy
The sun emits an enormous amount of electromagnetic radiation (solar energy) that spans a broad swath of the electromagnetic spectrum, the range of all possible radiation frequencies. When solar radiation reaches Earth, a fraction of this energy interacts with and may be transferred to the matter on the planet. This energy transfer results in a wide variety of different phenomena, from influencing weather patterns to driving a myriad of biological processes. In BIS2A, we are largely concerned with the latter, and below, we discuss some very basic concepts related to light and its interaction with biology.
Chlorophyll (also chlorophyl) is any of several related green pigments found in cyanobacteria and the chloroplasts of algaeand plants.[1] Its name is derived from the Greek words chloros ("green") and phyllon ("leaf").Chlorophyll is essential in photosynthesis, allowing plants to absorb energy from light.
Chlorophylls absorb light most strongly in the blue portion of the electromagnetic spectrumas well as the red portion. Conversely, it is a poor absorber of green and near-green portions of the spectrum, which it reflects, producing the green color of chlorophyll-containing tissues. Two types of chlorophyll exist in the photosystems of green plants: chlorophyll a and b.
Carotenoids are More than Just Accessory Pigments. Becausecarotenoids assist in absorbing photons for photosynthesis, they have been called accessory pigments. ... When just enough light reaches a leaf, it is used to move electrons and protons so the leaf can make sugars during photosynthesis.
ANTHOCYANINS:
The protective functions that have been ascribed to anthocyanins in leaves can be performed as effectively by a number of other compounds. The possibility that anthocyanins accumulate most abundantly in leaves deficient in other phytoprotective pigments has been tested. Pigment concentrations and their histological distribution were surveyed for a sample of 1000 leaves from a forest population of Quintinia serrata, which displays natural polymorphism in leaf colour. Eight leaf phenotypes were recognized according to their patterns of red coloration. Anthocyanins were observed in almost all combinations of every leaf tissue, but were most commonly located in the vacuoles of photosynthetic cells. Red leaves contained two anthocyanins (Cy-3-glc and Cy-3-gal), epicuticular flavones, epidermal flavonols, hydroxycinnamic acids, chlorophylls, and carotenoids. Green leaves lacked anthocyanins, but had otherwise similar pigment profiles. Foliar anthocyanin levels varied significantly between branches and among trees, but were not correlated to concentrations of other pigments. Anthocyanins were most abundant in older leaves on trees under canopies with south-facing gaps. These data indicate that anthocyanins are associated with photosynthesis, but do not serve an auxiliary phytoprotective role. They may serve to protect shade-adapted chloroplasts from brief exposure to high intensity sunflecks.
To perform photosynthesis, plants need three things: carbon dioxide, water, and sunlight. forphotosynthesis. ... The energy from light causes a chemical reaction that breaks down the molecules of carbon dioxide and water and reorganizes them to make the sugar (glucose) and oxygen gas.
Why might plants have more than one kind of pigment?
Because they interact with light to absorb only certain wavelengths,pigments are useful to plants and other autotrophs --organisms which make their own food using photosynthesis. In plants, algae, and cyanobacteria, pigments are the means by which the energy of sunlight is captured for photosynthesis.
How to different wavelength of light support photosynthesis?
Photosynthesis at different wavelengths. (a) The action spectrum of photosynthesis in plants; that is, the ability of light of different wavelengths to support photosynthesis. (b) The absorption spectra for threephotosynthetic pigments.
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