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autotrophic or heterotrophic nutrition
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Chapter 10
AP Biology
| Question | Answer |
|---|---|
| photosynthesis | conversion of light energy to chemical energy that is stored in sugars or other organic compounds; occurs in plants, algae, and certain prokaryotes |
| autotrophic or heterotrophic nutrition | 2 modes by which organisms acquire organic compounds it uses for energy and carbon skeletons |
| autotroph | self-feeder/producer; sustain themselves without eating anything derived from other living beings; produce organic molecules from CO2; ultimate source of organic compounds for nonautotrophs |
| photoautotrophs | organisms that use light as a source of energy to synthesize organic substances |
| heterotrophs | obtain organic material by secondary mode of nutrition; consumers |
| photosynthetic prokaryote that lived inside eukaryotic cell | original chloroplast believed to be: |
| half a million | _______ chloroplats per square inch of leaf surface |
| chlorophyll | green pigment located within chloroplasts |
| mesophyll | tissue in the interior of the leaf; where most chloroplasts are found |
| stomata | microscopic pores in which CO2 enters the leaf and oxygen exits |
| 30-40 | typical mesophyll cell has _________ chloroplasts |
| stroma | dense fluid within chloroplast enveloped by 2 membranes |
| thylakoids | elaborate system of interconnected membranous sacs which segregates stroma from thylakoid space |
| 6 (CO2) + 12 (H2O) + light energy --> (C6H12O6) + 6 (O2) + 6 (H2O) | photosynthesis equation |
| H2O | O2 given off by plants is derived from ____ and not from CO2 |
| Van Niel | challenged idea that photosynthesis splits CO2; photosynthetic organisms require hydrogen source but that source varies |
| endergonic | photosyntheis is (endergonic/exergonic) |
| light reactions and the Calvin cycle | 2 stages of photosynthesis |
| light reactions | steps of photosynthesis that convert solar energy to chemical energy |
| NADP+ | electron acceptor used in light reactions |
| photophosphorylation | process of generating ATP from ADP and phosphate by means of a proton-motive force generated across the thylakoid membrane during light reactions |
| carbon fixation | initial incorporation of carbon from CO2 into an organic compound by an autotrophic organism |
| Calvin cycle; light reactions | _______ makes sugar, but can only do so with help of NADPH and ATP produced by _________ |
| thylakoids | site of light reactions |
| stroma | site of Calvin cycle |
| wavelength | distance between crests of electronmagnetic waves |
| electromagnetic spectrum | entire range of electromagnetic radiation |
| visible light | wavelength from about 380nm-750 nm in wavelength; can be detected as colors by human eye |
| photons | particles of light (though not tangiable) with a fixed quantity of energy which is inversely related to the wavelength of light |
| pigments | substances that absorb visible light |
| spectrophotometer | directs beam of light of different wavelengths through a solution of the pigment and measures the fraction of the light transmitted at each wavelength |
| absorption spectrum | graph plotting a pigment's light absorption versus wavelengths |
| chlorophyll a | photosynthetic pigment that participates directly in light reactions, which converts solar energy to chemical energy; blue green with functional group CH3 |
| chlorophyll b | group of accessory pigments that transfer energy to chlorophyll a; olive green with functional group CHO |
| action spectrum | profiles relative effectiveness of different wavelengths of radiation in driving photosynthesis; illuminates chloroplasts with light of different colors and plots wavelength against photosynthetic rate |
| violet-blue and red light (note: green least effective) | best wavelength spectrums for photosynthesis (colors) |
| Engelmann | performed experiment which predated action spectrum; used bacteria to measure rates of photosynthesis in algae |
| carotenoids | accessory pigment; hydrocarbons that are various shades of yellow and orange which absorb violet and blue-green light; broaden spectrum that can drive photosynthesis |
| photoprotection | function of carotenoids; absorb and dissipate excessive light energy that would otherwise damage chlorophyll or interact with oxygen, forming reactive oxidative molecules that are dangerous to the cell |
| phytochemicals | compounds with antioxidant proprties |
| raises; ground; excited (note: electron cannot remain there long) | absorption of a photon _____ an electron from the _____ state to the ______ state |
| fluorescence | as excited electron fall back to the ground state, photons are given off, making an afterglow |
| photosystem | light-capturing unit located in thylakoid membrane consisting of a reaction-center complex surrounded by numerous light-harvesting complexes |
| reaction-center complex | complex of proteins associated w/ pair of chlorophyll a molecules and primary electron acceptor; located centrally in photosystem, triggers light reactions of photosynthesis |
| light-harvesting complex | complex of proteins associated with pigment molecules that capture light energy and transfer it to reaction-center pigments in a photosystem |
| primary electron acceptor | specialized molecule that shares the reaction-center complex with a pair of chlorophyll a molecules and that accepts an electron from them |
| photosystem II | one of the two light-capturing units in a chloroplast's thylakoid membrane; 2 molecules of p700 chlorophyll a at its reaction center |
| photosystem I | one of the two light-capturing units in a chloroplast's thylakoid membrane; 2 molecules of p680 chlorophyll a at its reaction center |
| light harvesting complexes | act as an antenna for the reaction-center complex |
| solar-powered transfer of an electron from the reaction-center chlorophyll a pair ro the primary electron acceptor | |
| P680 (note: refers to wavelength that most effectively is absorbed) | reaction center of chlorophyll a of photosystem II |
| P700 (note: refers to wavelength that most effectively is absorbed) | reaction center of chlorophyll a of photosystem I |
| linear electron flow | occurs during light reaction of photosynthesis; flow of electrons through photosystems and other molecular components built into the thylakoid membrane to synthesize ATP and NADPH |
| P680+ | strongest biological oxidizing agent known |
| plastoquinone, cytochrome complex and plastocyanin | electron transport chain between PSII and PSII contains: |
| linear electron flow | light reactions use solar power to generate ATP and NADPH, which provide chemical energy and reducing power to the carbohydrate-synthesizing reactions of the Calvin cycle |
| cyclic electron flow | a route of electron flow during the light reactions of photosynthesis that involves only PSI and that produces ATP but not NADPH or O2 |
| certain bacterial groups | examples of organisms that use cyclic electron flow |
| cyclic electron flow | photoprotective; protects cells from light-induced damage |
| organic molecules; water | reffering to chemiosmosis: in mitochondria, high-energy electrons dropped down the transport chain are extracted from ______; in chloroplasts, the source is ________ |
| chemical energy from food molecules; light energy into chemical energy | mitochondria use chemiosmosis yo transfer ______ energy from food molecules to ATP; chloroplasts transform ________ into _______ in ATP |
| stroma | ATP is formed in the ______ in chloroplasts |
| citric acid cycle; Calvin cycle | while the ________ is catabolic, oxidizing glucose and using the energy to synthesize ATP; the _______ is anabolic, building carbohydrates from smaller molecules and consuming energy |
| CO2; sugar | carbon enters Calvin cycle in form of _____ and leaves in the form of _______ |
| glyceraldehyde-3-phosphate (G3P) | three-carbon sugar produced by Calvin cycle, which must take place 3 times to synthesize sugar |
| carbon fixation | initial incorporation of CO2 into organic material |
| rubsico | most abundant protein in chloroplasts and most abundant protein on earth; catalyzes carbon fixation in Calvin cycle (attaches CO2 to RuBP) |
| transpiration | evaporative loss of water from leaves |
| C3 plants | a plant that uses the Calvin cycle for the initial steps that incorporate CO2 into organic material, forming a 3-carbon compound (3-phosphoglycerate) as the first stable intermediate |
| C4 plants | a plant in which the Calvin cycle is preceded by reactions that incorportate CO2 into a 4-carbon compound, the end product of which supplies CO2 for the Calvin cycle |
| C3 plants | rice, wheat, soybeans; as CO2 becomes scarce within air spaces of leaf, rubisco can bind O2 in place of CO2 |
| photorespiration | a metabolic pathway that consumes oxygen and ATP, releases CO2 and decreases photosynthetic output; generally occurs on hot, dry, bright days, where stromata close and the oxygen concentration in the leaf exceeds that of CO2 |
| 50% | photorespiration can drain up to ____ of the carbon fixed by the Calvin cycle |
| sugar cane, corn, grass family | examples of C4 plants |
| bundle-sheath cells (note: Calvin cycle is confined to the chloroplasts of these cells) | in C4 plants, cells arranged into tightly packed sheaths around the veins of the leaf |
| mesophyll cells | in C4 plants, between bundle-sheaths and the leaf surface; more loosely arranged |
| PEP carboxylase | enzyme present in mesophyll cells; adds CO2 to PEP, forming thw 4-carbon product oxaloacetate; has much higher affinity for CO2 than rubsico and no affinity for O2 |
| C4 plants | cycylic series of reactions involving PEP carboxylase and the regeneration of PEP can be thought of as a CO2-concentrating pump that is powered by ATP; minimizes photorespiration and enhances sugar production |
| crassulacean acid metabolism (CAM) | an adaptation for photosynthesis in arid conditions; plant takes up CO2 and incorporates it into a variety of organic acids at night; during the day, CO2 is released from organic acids for use in the Calvin cycle |
| succulents: cacti, pineapples... | examples of CAM plants |
| CAM plants | a plant that uses crassulacean acid metabolism; with stomata closed during the day and open at night |
| C4 and CAM | 2 evolutionary solutions to the problem of maintaining photosynthesis with stomata partially or completely closed on hot, dry days |
Created by:
chloew101