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Definition
| The range of a pigment's ability to absorb various wavelengths of light; also a graph of such a range. |
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Term
Acetyl CoA
(Acetyl coenzyme A) |
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Definition
| The entry compound for the citric acid cycle in cellular respiration, formed from a fragment of pyruvate attached to a coenzyme. |
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Definition
| The amount of energy that reactants must absorb before a chemical reaction will start; also called free energy of activation. |
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Definition
| The specific region of an enzyme that binds the substrate and that forms the pocket in which catalysis occurs. |
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ATP
(adenosine triphophate) |
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Definition
| An adenine-containing nucleoside triphosphate that releases free energy when its phosphate bonds are hydrolyzed. This energy is used to drive endergonic reactions in cells. |
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Definition
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Definition
| The binding of a regulatory molecule to a protein at one site that affects the function of the protein at a different site. |
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Allosteric Site
(Regulatory Site) |
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Definition
| The site on the protein to which the regulatory molecule binds. |
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Definition
| A metabolic pathway that consumes energy to synthesize a complex molecule from simpler molecules. |
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Definition
| A complex of several membrane proteins that functions in chemiosmosis with adjacent electron transport chains, using the energy of H+ (proton) concentration gradient to make ATP. ATP synthases are found in the inner mitochondrial membranes of eukaryotic cells and in the plasma membranes of prokaryotes. |
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Term
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Definition
| An organism that obtains organic food molecules without eating other organisms or substances derived from other organisms. Autotrophs use energy from the sun or from oxidation of inorganic substances to make organic molecules from inorganic ones. |
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Definition
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Definition
| The second of two major stages in photosynthesis (following the light reactions)O, involving fixation of atmospheric CO2 and reduction of the fixed carbon into carbohydrate. |
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Definition
| The initial incorporation of carbon from CO2 into an organic compound by an autotrophic organism (a plant, another photosynthetic organism, or a chemoautotrophic prokaryote). |
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Definition
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Definition
| A chemical agent that selectively increases the rate of a reaction without being consumed by the reaction. |
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Definition
| The catabolic pathways of aerobic and anaerobic respiration, which break down organic molecules and use an electron transport chain for the production of ATP. |
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Definition
| An energy-coupling mechanism that ses energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work, such as the synthesis of ATP. |
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Term
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Definition
| A green pigment located in membranes within the chloroplasts of plants and algae an din the membranes of certain prokaryotes. Chlorophyll a participates directly in the light reactions, which convert solar energy to chemical energy. |
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Term
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Definition
| A chemical cycle involving 8 steps that completes the metabolic breakdown of glucose molecules begun in glycolysis by oxidizing acetyl CoA (derived from pyruvate) to CO2; occurs within the mitochondrion in eukaryotic cells and in the cytosol of prokaryotes; together with pyruvate oxidation, the second major stage in cellular respiration. |
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Term
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Definition
| A substance that reduces the activity of an enzyme by entering the active site in place of the substrate, whose structure it mimics. |
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Definition
| A route of electron flow during the light reactions of photosynthesis that involves only photosystem 1 and that produces ATP but not NADPH or O2. |
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Term
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Definition
| An iron-contianing protein that is a component of electron transport chains in the mitochondria and chloroplasts of eukaryotic cells and the plasma membranes of prokaryotic cells. |
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Definition
| A sequence of electron carrier molecules (membrane proteins) that shuttle electrons down a series of redox reactions that release energy used to make ATP. |
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Definition
| A non-spontaneous chemical reaction, in which free energy is absorbed from the surroundings. |
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Term
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Definition
| In cellular metabolism, the use of energy released from an exergonic reaction to drive and endergonic reaction. |
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Definition
| A measure of disorder, or randomness. |
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Definition
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Definition
| A method of metabolic control in which the end product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway. |
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Definition
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Definition
| A series of reactions that ultimately spits glucose into pyruvate. Glycolysis occurs in almost all living cells, serving as the starting point for fermentation or cellular respiration. |
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Definition
| A stack of membrane-bounded thylakoids in the chloroplast. Grana (pl.) function in the light reactions of photosynthesis. |
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Definition
| An organism that obtains organic food molecules by eating other organisms or substances derived from them. |
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Definition
| Glycolysis followed by the reduction of pyruvate to lactate regenerating NAD+ with no release of CO2. |
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Term
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Definition
| The first of 2 major stages in photosynthesis (preceding the Calvin Cycle). These reactions, which occur on the thylakoid membranes of the chloroplast or on membranes of certain prokaryotes, convert solar energy to the chemical energy of ATP and NADPH, releasing oxygen in the process. |
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Definition
| Leaf cells specialized for photosynthesis. |
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Term
Oxidative Phosphorylation |
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Definition
| The production of ATP using energy derived from the redox reactions of an electron transport chain; the third major stage of cellular respiration. |
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Term
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Definition
| The process of generating ATP from ADP and phosphate by means of chemiosmosis, using a proton-motive force generated acros the thylakoid membrane of the chloroplast or the membrane of certain prokaryotes during the light reactions of photosynthesis. |
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Term
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Definition
| A metabolic pathway that consumes oxygen and ATP, releases CO2, and decreases phtosynthetic output. Photorespiration generally occurs on hot, dry, bright days, when stomata close and the O2/CO2 ratio in the leaf increases, favoring the binding of 02 rather thatn CO2 by rubisco. |
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Term
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Definition
| A light-capturing unit located in the thylakoid membrane of the chloroplast or in the membrane of some prokaryotes, consisting of a reaction-center complex surrounded by numerous light-harvesting complexes. There are 2 types of photosystems, I and II; they absorb light best at different wavelengths. |
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Term
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Definition
| The energy that matter possesses as a result of its location or spatial arrangement (structure). |
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Term
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Definition
| The potential energy stored in the form of a proton electrochemical gradient, generated by the pumping of hydrogen ions (H+) across a biological membrane during chemiosmosis. |
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Definition
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Definition
| A complex of proteins associated with a special pair of chlorophyll a molecules and a primary electron acceptor. Located centrally in a photosystem, this complex triggers the light reactions of phtosynthesis. Excited by light energy, the pair of chlorophylls donates an electron to the primary electron acceptor, which passes an electron transport chain. |
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Term
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Definition
| A chemical reaction involving the complete or partial transfer of one or more electrons from one reactant to another; short for reduction-oxidation reaction. |
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Definition
| The electron donor in a redox reaction. |
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Definition
| A microscopic pore surrounded by guard cells in the epidermis of leaves and stems that allows gas exchange between the environment and the interior of the plant. |
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Definition
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Definition
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Definition
| A flattened, membranous sac inside a chloroplast. Thylakoids often exist in stacks called grana that are interconnected; their membranes contain molecular "machinery" used to convert light energy to chemical energy. |
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