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Biology Ch. 6
Term | Definition |
---|---|
Autotroph | An organism that produces its own nutrients from inorganic substances or from the environment instead of consuming other organisms |
Photosynthesis | The process by which plants, algae, and some bacteria use sunlight, carbon dioxide, and water to produce carbohydrates and oxygen |
Heterotroph | An organism that obtains organic food molecules by eating other organisms or their byproducts and that cannot synthesize organic compounds from inorganic materials |
Light Reactions | The initial reactions in photosynthesis, which are triggered by the absorption of light by photosystems I and II and include the passage of electrons along the electron transport chains, the production of NADPH and oxygen gas, and the synthesis of ATP thr |
Chloroplast | An organelle found in plant and algae cells where photosynthesis occurs |
Thylakoid | A membrane system found within chloroplasts that contains the components for photosynthesis |
Granum | A stack of thylakoids in a chloroplast |
Stroma | In plants, the solution that surrounds the thylakoids in a chloroplast |
Pigment | A substance that gives another substance or a mixture its color |
Chlorophyll | A green pigment that is present in most plant cells, that gives plants their characteristic green color, and that reacts with sunlight, carbon dioxide, and water to form carbohydrates |
Carotenoid | A class of pigments that are present mostly in plants and that aid in photosynthesis |
Photosystem | In the thylakoid membranes of chloroplasts, a cluster of chlorophyll and other pigment molecules that harvest light energy for the light reactions of photosynthesis |
Primary Electron Acceptor | In chloroplasts, an acceptor of electrons lost from a chlorophyll a; found in the thylakoid membrane |
Electron Transport Chain | A series of molecules, found in the inner membranes of mitochondria and chloroplasts, through which electrons pass in a process that causes protons to build up on one side of the membrane |
Chemiosmosis | In chloroplasts and mitochondria, a process in which the movement of protons down their concentration gradient across a membrane is coupled to the synthesis of ATP |
Calvin Cycle | A biochemical pathway of photosynthesis in which carbon dioxide is converted into glucose using ATP |
Carbon Fixation | The synthesis of organic compounds from carbon dioxide, such as in photosynthesis |
Stomata | One of many openings in a leaf or a stem of a plant that enable gas exchange to occur |
C4 Pathway | A carbon-fixing process in which carbon dioxide is bound to a compound to form a four-carbon intermediate |
CAM Pathway | Crassulacean acid metabolism, a biochemical pathway in certain plants in which carbon dioxide is incorporated into organic acids at night and released for fixation in the Calvin cycle during the day |