 | Term | Definition |
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Autotroph |
An organism that obtains organic food molecules without eating other organisms or substanes derived from other organisms. These use energy from the sun or from the oxidation of inorganic substances to make organic molecules from inorganic ones. |
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Heterotroph |
An organism that obtains organic food molecules by eating other organisms or their by-products. |
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Photosynthesis |
The conversion of light energy to chemical energy that is stored in glucose or other organic compounds; occurs in plants, algae, and certain prokaryotes. |
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Light reactions |
The steps in photosynthesis that occur on the thylakoid membranes of the chloroplast and that convert solar energy to the chemical energy of ATP and NADPH, evolving oxygen in the process. |
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Dark reactions |
The second of two major stages in photosynthesis, involving atmospheric CO2 fixation and reduction of the fixed carbon into carbohydrate. These reactions are also called the Calvin Cycle. |
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Photon |
A quantum, or discrete amount, of light energy. |
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Pigment |
What's developed in the thylakoid; the substance that makes the leaves green (hint: not clorophyll) |
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Excited state |
The state in which an electron jumps from a lower energy level to a higher energy level. |
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Ground state |
The state in which an electron stays in its normal state of energy. |
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Fluorescence |
The emission of visible light, especially of visible light, by a substance during exposure to external radiation, as light. |
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Primary electron acceptor |
A specialized molecule sharing the reaction center with the pair of reaction-center chlorophyll a molecules; it accepts an electron from one of these two chlorophylls. |
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Thylakoid |
A flattened membrane sac inside the choloroplast, used to convert light energy to chemical energy. |
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Stroma |
The fluid of the chloroplast surrounding the thylakoid membrane; involved in the synthesis of organic molecules from carbon dioxide to water. |
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Electron transport chain |
A sequence of electron carrier molecules that shuttle electrons during the redox reactions that release energy used to make ATP. |
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Calvin Cycle |
The part of photosynthesis that doesn't necessarily require light; also known as dark reactions. |
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Rubisco |
Ribulose carboxylase, the enzyme that catalyzes the first step of the Calvin Cycle (the addition of CO2 to ribulose biphosphate, or RuBP). |
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Photorespiration |
A metabolic pathway that consumes oxygen, releases carbon dioxide, generates no ATP, and decreases photosynthetic output; generally occurs on hot, dry, bright days, when stomata close and the oxygen concentration in the leaf exceeds that of carbon dioxide. |
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Carbon fixation |
The incorporation of carbon from carbon dioxide into an organic compound by an autotrophic organism. |
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