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Chapter 6
Vocabulary
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, |
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 of 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 chloroplast, an acceptor of electrons lost from chlorophylla; 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 | plants lose water through these small pores in hot and dry conditions, usually located on the undersurface of the leaves. |
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 |