Term
| adenosine triphosphate (ATP) |
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Definition
| Short term energy carrier molecule. In the light dependent reactions, molecules in the membranes of the thylakoids capture sunlight energy and convert some of it into chemical energy stored, for the short term in one of two different energy carrier molecules. One of which is ATP the other is NADPH. |
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Term
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Definition
| One of a group of cells that surround the veins of plants; in c4 (but not c3) plants, bundle-sheath cells contain chloroplasts.In the bundle-sheath cells oxaloacete breaks down, releasing C02 again. This release creates a high C02 concentration so the c3 cycle can proceed with less competition from oxygen. |
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Term
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Definition
| the cyclic series of reactions whereby carbon dioxide is fixed into carbohydrates during the light-independent reactions of photosynthesis; also called Calvin-Benson cycle. |
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Definition
| the series of reactions in certain plants that fixes carbon dioxide into oxaloacetic acid, with is later broken down for use in the C3 cycle of photosynthesis. |
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Definition
| the initial steps in the C3 cycle, in which carbon dioxide reacts with ribulose bisphosphate to form a stable organic molecule. |
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Term
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Definition
| a pigment found in chloroplasts that captures light energy during photosynthesis; absorbs violet, blue, and red light but reflects green light. Tends to break down quickly when the leaf dies so the leaf is no longer green. |
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Term
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Definition
| the organelle in plants and plantlike protists that is the site of photosythesis; surrounded by a double membrane and containing an extensive internal membrane system that bears chlorophyll. |
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Term
| electron transport chain (ETC) |
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Definition
| a series of electron carier molecules, found in the thylakoid membrane of chloroplasts and the inner membrane of mitochondria, that extract energy from electrons and generate ATP or other energetic molecules. |
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Term
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Definition
| in photosystems, the assembly of pigment molecules (chlorophyll and accessory pigments) that absorb light energy and transfer that energy to electrons. |
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Term
| light-dependent reactions |
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Definition
| The first stage of photosynthesis, in which the energy of light is captures as ATP and NADPH; occures in the thylakoids of chloroplasts. |
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Term
| light-independent reactions |
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Definition
| The second stage of photosynthesis, in which the energy obtained by the light-dependent reations is used to fix carbon dioxide into carbohydrates; occurs in the stroma of chloroplasts. |
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Term
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Definition
| loosly packed parenchyma cells beneath the epidermis of a leaf |
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Term
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Definition
| a plant cell type that is alive at maturity, normally with thin primary cell walls, that carries out most of the metabolism of a plant. Most dividing cells in a plant are parenchyma. |
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Term
| nicotinamide adenine dinucleotide phosphate (NADPH) |
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Definition
| an energy-carrier molecule produced by the light-dependent reactions of photosynthesis; transfers energy to the carbon-fixing reactions (light-independent) reactions. |
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Term
| phosphoenolpyruvate (PEP) |
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Definition
| a three-carbon sugar that is an important component of the C3 cycle in the light-independant reactions of photosynthesis. |
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Term
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Definition
| a series of reactions in plants in which 02 replaces CO2 during the C3 cycle, preventing carbon fixation; this wasteful process dominates when C3 plants are forced to close their stomata to prevent water loss. |
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Term
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Definition
| the complete series of chemical reactions in which the energy of light is used to synthesize high-energy organic molecules, normally carbohydrates, from low-energy inorganic molecules, normally carbon dioxide and water. |
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Term
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Definition
| in thylakoid membranes, a light-harvesting complex and its associated electron transport system. |
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Term
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Definition
| in the light-harvesting complex of a photosystem, the chlorophyll molecule to which light energy is transferred by the antenna molecules (light-absorbing pigments); the captured energy ejects an electron from the reaction center chlorophyll, and the electron is transfered to the electron transport system. |
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Term
| ribulose bisphospate (RuBP) |
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Definition
| a six-carbon molecule that reacts with carbon dioxide in the carbon-fixing reaction of C3 photosynthesis; an inportant participant in the Calvin-Benson C3 cycle. |
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Term
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Definition
| (plural of stoma) the adjustable openings in the epidermis of a leaf, surrounded by a pair of gaurd cells, that regulates the diffusion of carbon dioxide and water into and out of the leaf. |
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Term
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Definition
| the semifluid material inside chloroplasts in which the grana are embedded. |
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Term
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Definition
| A series of stacked thylakoid disks containing chlorophyll; found in the inner membrane of chloroplasts. |
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Term
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Definition
| a disk-shaped, membranous sac found in chloroplasts, the membranes of which contain the photosystems and ATP-synthesizing enzymes used in the light-depentent reactions of photosynthesis. |
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Term
| photosynthesis is highest in |
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Definition
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Term
| Where do the light-dependent reactions of photosynthisis occur? |
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Definition
| within the thylakoid membranes of the chloroplast |
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Term
| The oxygen produced during photosynthesis comes from |
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Definition
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Term
| The role of accessory pigments is to |
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Definition
| capture additional light energy and transfer it to the chlorophyll reaction centers |
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Term
| Where do the light-independent, carbon-fixing reactions occur? |
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Definition
| in the chloroplast stroma |
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Term
| What features do leaves have that make them well suited for photosynthesis? |
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Definition
| Leaves of most land plants are only a few cells thick. Having thin leaves ensures that sunlight can easly penetrate them. In addition, the flattened shape of leaves exposes a large surface area to the sun. |
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Term
| Name an accessory pigment and tell what colors it reflects. |
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Definition
| Carotenoids absorb blue and green light, but reflect yellow and orange. |
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Term
| Light energy is initially captured by photosystems within thylakoid membranes. Photosystems are organized arrays of _________, _________, and ________, |
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Definition
| proteins, chlorophyll molecules, pigment molecules such carotenoids. |
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Term
| Why is carbon dioxide a key molecule in the light-independent reactions of photosynthesis? |
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Definition
| Carbon dioxide is a raw material for sugar production in the light-independent reactions. |
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Term
| What is photorespiration? |
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Definition
| Photorespiration prevents sugar production when C02 levels are low and O2 levels are high. |
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Term
| During photosynthesis, electrons are continuosly lost from the reaction center of photosystem II. What source is used to replace these electrons? |
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Definition
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Term
| The term carbon fixation refers to |
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Definition
| the incorporation of carbon from carbon dioxide into a larger molecule. |
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Term
| How have C4 plants adapted to environmental conditions that would result in increased photorespiration? |
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Definition
1. C4 plants have substituted phophoenolpyruvate (PEP) for ribulose bisphosphate.
2. PEP combines with carbon dioxide even in the face of high oxygen concentrations.
3. Oxaloacetate transports fixed carbon into bundle-sheath cells, where the normal C3 cycle can proceed. |
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Term
| The stomata allow _________ to exit the leaf. |
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Definition
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Term
Which of the following is NOT required for the light-independent reactions of photosynthesis?
ATP, NADPH, CO2, H2O, O2 |
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Definition
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Term
| What kind of light would have the most photosynthesis? |
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Definition
| Red and Blue light combined. |
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Term
| The oxygen produced during photosynthesis comes from the |
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Definition
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Term
| The role of accessory pigments is to |
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Definition
| capture and transfer light energy to the reaction centers. |
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Term
| Where do the light-independent, carbon fixing reactions occur? |
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Definition
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Term
| Where do the light-dependent reactions of photosynthesis occur? |
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Definition
| in the thylakoid membranes. |
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Term
| How is light energy converted to chemical energy? Name the three processes that the energy of these electrons drives. |
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Definition
light-dep. react. occur in the thylakoids. Light excites electrons in chlorophyll and transfers the energetic electrons to electron transport chains. A)Photosys. II which generates ATP. Some of the energy from the electrons is used to drive ATP synthesis.
B)Photosys.I generates NADPH. Some of the energy, in the form of energetic electrons, is added to electron-carrier NADP+ to make the energetic carrier NADPH. C)Splitting water maintains the flow of electrons through the photosys.Some of the energy is used to split water, generating the electrons needed by photosys.II and producing hydrogen ions and oxygen. |
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Term
| Name the three light-independent reactions that constitute the C3 cycle |
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Definition
A)Carbon fixation. Carbon dioxide and water combine with RuBP to form PGA.
B)Synthesis of G3P. PGA is converted to G3P, using energy form ATP and NADPH.C)RuBP synthesis-G3P is used to regenerate RuBP to restart cycle. |
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Term
| What energy drives the light-independent reactions? |
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Definition
| both ATP and NADPH provide the energy that synthesize glucose from CO2 and H2O. |
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Term
| What is the relationship between light-dependent reactions and light-independent reactions? |
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Definition
| The light-dependent reactions produce the energy carrier ATP and the electron carrier NADPH. Energy from these carriers is used in the synthesis of organic molecules during the light-independent reactions. The depleted carriers, ADP and NADP+, return to the light-dependent reactions for recharging. |
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Term
| Which photosystem happens first? |
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Definition
| Photosystem II (it was just discovered second). |
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