bio midterm2

bio midterm2 - Visible light represents a very small...

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Visible light represents a very small portion of a vast continuous range of radiation called the electromagnetic spectrum . All radiation in this spectrum travels as waves. At one end of the spectrum are gamma rays , which are very short in length and measured in nanometers (a billionth of a meter). At the other end are radio waves , which are very long and measured in kilometers. The portion from 380 to 760 nm is called the visible spectrum. Violet has the shortest wavelength while red has the longest. Light is composed of small particles of energy called photons. Energy of a photon is inversely related to its wavelength . The shorter the wavelength, the more energy per photon there is. Chlorophyll absorbs light primarily in the blue and red regions of the vls (visible light spectrum). Green light is not absorbed by Chlorophyll. Chlorophyll-a is the pigment that initiates the light-dependent reactions of photosynthesis. Chlorophyll-b is an accessory pigment that also participates in photosynthesis. It differs from chlorophyll-a only in a functional group on the porphyrin ring. Carotenoids are photosynthetic pigments which are yellow and orange. An action spectrum is a graph of relative effectiveness of different wavelengths of light. An absorption spectrum is a plot of its absorption of light of different wavelengths. Green alga- spirogyra. .long filamentous strands in freshwater. Cells contain long spiral shaped emerald green chloroplast embedded in cytoplasm. Engleman, a scientist, found out that chlorophyll in the chloroplasts is responsible for photosynthesis.
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Photosynthesis equation = 6 co2 + 6 h2o c6 h12 o6 + 6 o2 Photosynthesis has two parts: the light dependent reactions and the carbon fixation reactions. The light dependent reactions occur in the thylakoids and the carbon fixation reactions occur in the stroma. Light energy is converted to chemical energy in the light dependent reactions which are associated with the thylakoids. It begins as chlorophyll captures light, causing one electron to move higher in energy. The electron is transferred and is replaced by electron from H2o. H2o splits and molecular oxygen is released. This ultimately forms ATP and NADPH. The ATP and NADPH in light reactions transfer energy to chemical bonds in carbohydrates. These reactions fix carbon atoms from Co2 to existing skeletons of organic molecules. The light dependent reactions being when chlorophyll-a and/or
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This note was uploaded on 10/10/2010 for the course BIO 101 taught by Professor Martin during the Spring '08 term at Rutgers.

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bio midterm2 - Visible light represents a very small...

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