study guide lectures 21-31

Study guide - 21-22 study guide(21-22.1)photoautotroph organism that uses light as a source of energy to synthesize organic

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Unformatted text preview: 21-22 study guide:(21-22.1)photoautotroph: organism that uses light as a source of energy to synthesize organic substancesexamples-multicellular algae, plants, unicellular protests, cyanobacteria, and purple sulfur bacteriaheterotrophs: organisms that live on compounds produced by other organisms(21-22.2)Photosynthesis “final” chemical equation: CO + H O [CH O] + O The carbohydrate is glucose, C H O .Photosynthesis is mainly carried out in mesophyll cells, the tissue in the interior of the leaf.(21-22.3)Photosynthesis is an oxidation-reduction reaction.6CO + 12H O C H O + 6H O + 6OLight provides the energy for this process. Energy is required because the electrons increase in potential energy as they move from water to sugar.(21-22.4)In the electromagnetic spectrum, gamma rays are the most dangerous. The amount of energy is inversely related to the wavelength of the light. Radiation is minimized on earth by the atmosphere. The atmosphere acts like a selective window, allowing visible light to pass through while screening out a substantial fraction of other radiation.Visible light drives photosynthesis and is the ultimate source for life on earth.(21-22.5)An object that appears black in color has absorbed all wavelengths. An object thst is white in color does not absorb any wavelengths.(21-22.6)Plants absorb light between the wavelengths of ~430-480 and ~640-680 nanometers because violet blue and red light work best for photosynthesis. Light can perform work only if it is absorbed.Accessory pigments with different absorption spectra are photosynthetically important in chloroplasts and broaden the spectrum of colors that can be used for photosynthesis.carotenoids: hydrocarbons that are various shades of yellow and orange because they absorb violet and blue-green light; photoprotection-absorb and dissipate excessive light energy. Serve as photoprotective role in human eye.(21-22.7)Chlorophyll a and chlorophyll b differ only in one of the functional groups bonded to the porphyrin ring. Chlorophyll a and chlorophyll b have slightly different absorption spectra and chlorophyll a is blue-green, whereas chlorophyll b is yellow-green.The light-absorbing porphyrin head of the chlorophyll molecule is found in the thylakoid membrane of the chloroplast.(21-22.8)Step 1: A photon of light strikes the light harvesting complex and excites one of the P680 electrons to a higher energy state.Step 2: This electron is captured by the primary electron acceptor.Step 3: When a water molecule is split, the two electrons are supplied one by one to the P680 molecules and the two oxygen atoms combine to form O2.Step 4: Each photoexcited electron passes from the primary electron acceptor of photosystem II to photosystem I via an electron transport chain....
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This note was uploaded on 05/29/2008 for the course BIOLOGY 102 taught by Professor Rhondanicholson during the Spring '07 term at Temple.

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Study guide - 21-22 study guide(21-22.1)photoautotroph organism that uses light as a source of energy to synthesize organic

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