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| an organism that makes its own food, thereby sustaining itself without eating other organisms or their molecules. Plants, algae, and photosynthetic bacteria are autotrophs. |
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| an organism that makes organic food molecules from CO2, H2O, and other inorganic raw materials: a plant, alga, or autotrophic bacterium. |
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| an organism that obtains energy from sunlight and carbon from CO2 by photosynthesis. |
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| the green tissue in the interior of a leaf; a leaf's ground tissue system; the main site of photosynthesis. |
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| a pore surrounded by guard cells in the epidermis of a leaf. When stomata are open, CO2 enters a leaf, and water and O2 exit. A plant conserves water when its stomata are closed. |
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| a thick fluid enclosed by the inner membrane of a chloroplast. Sugars are made in the stroma by the enzymes of the Calvin cycle. |
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| one of a number of disk-shaped membranous sacs inside a chloroplast. Thylakoid membranes contain chlorophyll and the enzymes of the light reactions of photosynthesis. A stack of thylakoids is called a granum. |
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| a stack of hollow disks formed of thylakoid membrane in a chloroplast. Grana are the sites where light energy is trapped by chlorophyll and converted to chemical energy during the light reactions of photosynthesis. |
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| the first of two stages in photosynthesis; the steps in which solar energy is absorbed and converted to chemical energy in the form of ATP and NADPH. The light reactions power the sugar-producing Calvin cycle but produce no sugar themselves. |
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| the second of two stages of photosynthesis; a cyclic series of chemical reactions that occur in the stroma of a chloroplast, using the carbon in CO2 and the ATP and NADPH produced by the light reactions to make the energy-rich sugar molecule G3P. |
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| the incorporation of carbon from atmospheric CO2 into the carbon in organic compounds. During photosynthesis in a C3 plant, carbon is fixed into a three-carbon sugar as it enters the Calvin cycle. In C4 and CAM plants, carbon is fixed into a four-carbon sugar. |
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| solar energy, or radiation, which travels in space as rhythmic waves and can be measured in photons. |
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| the distance between crests of adjacent waves, such as those of the electromagnetic spectrum. |
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| a fixed quantity of light energy. The shorter the wavelength of light, the greater the energy of a photon. |
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| a light-capturing unit of a chloroplast's thylakoid membrane, consisting of a reaction center surrounded by numerous lightharvesting complexes. |
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| in a photosystem in a chloroplast, the chlorophyll a molecule and the primary electron acceptor that trigger the light reactions of photosynthesis. The chlorophyll odnates na electron excited by light energy to the primary electron acceptro, which passes an electron to an electron transport chain. |
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| the production of ATP by chemiosmosis during the light reactions of photosynthesis. |
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| a plant that uses the Calvin cycle for the initial steps that incorporate CO2 into organic material, forming a three-carbon compound as the first stable intermediate. |
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| in a plant cell, the breakdown of a two-carbon compound produced by the Calvin cycle. The Calvin cycle produces the two-carbon compound, instead of its usual three-carbon product G3P, when leaf cells fix O2, instead of CO2. Photorespiration produces no sugar molecules or ATP. |
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| a plant that prefaces the Calvin cycle with reactions that incorporate CO2 into four-carbon compounds, the end product of which suppplies CO2 for the Calvin cycle. |
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| a plant that uses cassulacean acid metabolism, an adaptation for photosynthesis in arid conditions. Carbon dioxide entering open stomata during the night is converted to organic acids, which release CO2 for the Calvin cycle during the day, when stomata are closed. |
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| the warming of the atmosphere caused by CO2, CH4, and other gases that absorb infrared radiation and slow its escape from Earth's surface. |
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| a slow but steady rise in Earth's surface temperature, caused by increasing concentration of greenhouse gases (such as CO2 and CH4) in the atmosphere. |
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