Term
|
Definition
| green plants, algae and certain bacteria use light energy to make sure from carbon dioxide & water. they also produce oxygen we need to breathe & store an energy source that could help solve the human power problem |
|
|
Term
| how are carbon dioxide & water involved in cellular respiration? |
|
Definition
| they are the waste products of it |
|
|
Term
| how do plants take in the waste products of cell. respiration (C02 and H2O)? |
|
Definition
| by absorbing CO2 through their leaves & pulling H2O through their roots |
|
|
Term
| what absorbs the solar energy of sunlight on a plant? |
|
Definition
|
|
Term
| how does the molecular shuffling of the absorption occur? |
|
Definition
| six mols of CO2 and six mols of H2O are converted to one mol of sugar glucose & six mols of oxygen gas |
|
|
Term
| how much carbohydrate is made each year by plants? |
|
Definition
| 160 billion metric tons (176 billion tons) |
|
|
Term
| which plant has shown promise as fuel to grow & burn in power generation facilities? & why? |
|
Definition
| willow b/c it grows quickly and resprouts once they are cut, also pack more fuel & power than most native trees |
|
|
Term
| where does the carbon dioxide released from burning fossil fuels come from? |
|
Definition
| it releases CO2 that was removed from the atmosphere hundreds of million years ago |
|
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Term
|
Definition
| make their own food and thus sustain themselves w/o eating other organisms or even organic molecules |
|
|
Term
| what do the chloroplasts do? |
|
Definition
| capture light energy that has traveled 150 million kilometers from the sun & convert it to chemical energy that is stored in sugar and other organic molecules |
|
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Term
|
Definition
| they produce their own food supply |
|
|
Term
| what are other producers except plants |
|
Definition
| algae, certain other protists, some prokaryotes |
|
|
Term
|
Definition
| all organisms that produce organic molecules from inorganic molecules using the energy of light |
|
|
Term
| main food producers in aquatic environments |
|
Definition
| algae & photosynthetic bacteria |
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|
Term
| important producers in freshwater & marine ecosystem |
|
Definition
| prokaryotic cyanobacteria |
|
|
Term
| what do autotrophs require from the environment in order to synthesize sugar? |
|
Definition
|
|
Term
|
Definition
| a light0absorbing pigment in the chloroplasts that plays a a central role in converting solar energy to chemical energy |
|
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Term
|
Definition
| the green tissue in the interior of the leaf where chloroplasts are concentrated in the cells |
|
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Term
|
Definition
| tiny pores where CO2 enters the leaf & O2 exists |
|
|
Term
| what do membranes in the chloroplast do? |
|
Definition
| they form the framework where many of the rxns of photosynthesis occur |
|
|
Term
|
Definition
| a thick fluid in the 2nd comparment enclosed by the chloroplast's inner membrane where sugars are made from CO2 and H20 |
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|
Term
|
Definition
| a system of interconnected membranous sacs suspended in the stroma which enclose a 3rd chloroplast compartment (the thylakoid space) |
|
|
Term
|
Definition
| the name for thylakoids that are concentrated in stacks |
|
|
Term
| what is built into the thylakoid membranes? |
|
Definition
| the chlorophyll molecules that capture light energy |
|
|
Term
| what do thylakoid membranes also do? |
|
Definition
| they house much of the machinery that converts light energy to chemical energy |
|
|
Term
| what are the bubbles that are on the leaves of plants that live in lakes/ponds? |
|
Definition
| oxygen gas produced during photosynthesis |
|
|
Term
| what did scientists in 1800s think of how plants produce 02? |
|
Definition
| by extracting it from CO2 |
|
|
Term
| what did scientists in 1950s do? |
|
Definition
| tested the 1800 hypothesis by using a heavy isotope of oxygen to follow the fate of oxygen atoms during photosynthesis |
|
|
Term
| what does the photosynthesis equation show about water? |
|
Definition
| it is a reactant & product in the reaction |
|
|
Term
| how do plants produce O2 gas? |
|
Definition
|
|
Term
| what step in cellular respiration reverses the water-splitting step of photosynthesis? |
|
Definition
| the formation of water when elections & hydrogen ions are added to oxygen at the "bottom" of the electron transport chain |
|
|
Term
| what is the food-producing equation for photosynthesis? |
|
Definition
|
|
Term
| what kind of process is photosynthesis? |
|
Definition
|
|
Term
|
Definition
|
|
Term
| what happens when the water molecules are split apart |
|
Definition
| they yield O2 - they are actually oxidized - they lose electrons, along with hydrogen ions. MEANWHILE : CO2 is reduced to sugar as electrons & hydrogen ions are added to it |
|
|
Term
| how does cellular respiration harvest energy stored in a glucose molecule? |
|
Definition
| by oxidizing the sugar & reducing 02 to H2O |
|
|
Term
| what happens w/ the electrons during the energy-releasing part of photosynthesis? |
|
Definition
| electrons lose potential energy as they travel down an energy hill from sugar to O2. along the way, mitochondrion uses some of the energy to synthesize ATP |
|
|
Term
| what happens to the electrons as water is oxidized & CO2 is reduced? |
|
Definition
| electrons gain energy by being boosted up an energy hill |
|
|
Term
| what provides the boost for the electrons? |
|
Definition
| the light energy captured by chlorophyll molecules in the chloroplast |
|
|
Term
|
Definition
| the steps that convert light energy to chemical energy & produce O2 gas as a waste product |
|
|
Term
| where do light reactions occur |
|
Definition
|
|
Term
| in light rxns, what is used to make ATP from ADP & phosphate |
|
Definition
| light energy absorbed by chlorophyll molecules built into the membranes |
|
|
Term
| in light rxns, what drives a transfer of electrons from water to NADP+ |
|
Definition
|
|
Term
|
Definition
| an electron carrier similar to NAD+ that carries electrons in cellular respiration |
|
|
Term
| how do enzymes reduce NADP+ TO NADPH in the light rxns |
|
Definition
| by adding a pair of light-excited electrons along with an H+ |
|
|
Term
| is water split & O2 released in the light rxns or calvin cycle |
|
Definition
|
|
Term
| is sugar made in the light rxns or the calvin cycle |
|
Definition
|
|
Term
| in summary, the light rxns of photosynthesis are the steps that absorb ____ energy & convert it to _____ energy stored in _____ & ______ |
|
Definition
| solar; chemical; ATP; NADPH |
|
|
Term
| where does the calvin cycle occur |
|
Definition
| in the stroma of the chloroplast |
|
|
Term
|
Definition
| a cyclic series of reactions that assembles sugar molecules using CO2 and the energy-containing products of the light reactions |
|
|
Term
| American biochemist & Nobel laureate who the calvin cycle is named after |
|
Definition
|
|
Term
| what did Melvin Calvin do? |
|
Definition
| in 1950s, him & his colleagues traced the path of carbon in the cycle, using the radioactive isotope 14C to label the carbon in CO2 |
|
|
Term
|
Definition
| the incorporation of isotope 14C to label the carbon in CO2 into organic compounds. after carbon fixation, enzymes of the cycle make sugars by further reducing the carbon compounds |
|
|
Term
| ____ produced by the light reaction provides _____ electrons for reducing ____ in the calvin cycle. ____ from the light rxns provides _____ energy that powers several of the steps of the calvin cycle |
|
Definition
| NADPH; high-energy; carbon. ATP; chemical |
|
|
Term
| in most plants, in what time of the day does the calvin cycle run? |
|
Definition
| during daytime when the light rxns power the cycle's sugar assembly line by supplying it with NADPH & ATP |
|
|
Term
| does the calvin cycle require direct light? |
|
Definition
|
|
Term
|
Definition
| light - light rxns ; putting together - sugar construction by the calvin cycle |
|
|
Term
|
Definition
| travels in space as rhythmic waves analogous to those made by a pebble dropped in a puddle of water |
|
|
Term
|
Definition
| the distance b/w the crests of 2 adjacent waves |
|
|
Term
| wavelength of visible light |
|
Definition
|
|
Term
| difference b/w short & long wavelengths |
|
Definition
| shorter wavelengths have more energy than longer ones |
|
|
Term
| why is UV radiation in sunlight can cause sunburns & skin cancer? |
|
Definition
| b/c since they are so short, they have enough energy to damage organic molecules such as proteins & nucleic acids |
|
|
Term
| what happens to visible light in the chloroplast |
|
Definition
| pigments absorb some wavelengths of light & reflect/transmit other wavelengths |
|
|
Term
|
Definition
| light-absorbing molecules built into the thylakoid membranes |
|
|
Term
| why do we not see the absorbed wavelengths in the chloroplast? |
|
Definition
| b/c their energy has been absorbed by pigment molecules |
|
|
Term
| what do we see when we look at a leaf? |
|
Definition
| the green wavelengths that the pigments transmit & reflect |
|
|
Term
| chlorophyll A & what does it have to do w/ light rxns |
|
Definition
| a pigment in chloroplasts that absorbs mainly blue-violent & red light. it looks grass-green b/c it reflects mainly green light. it participates DIRECTLY in light rxns |
|
|
Term
| chlorophyll B & how does it broaden the range of light that a plant can use? |
|
Definition
| absorbs mainly blue & orange light and reflects (appears) yellow-green. it broadens the range of light that a plant can use by conveying absorbed energy to chlorophyll A, which then puts the energy to work in the light rxn |
|
|
Term
|
Definition
| a family of yellow-orange pigments which absorb mainly blue-green light |
|
|
Term
| what 2 things can carotenoids do? |
|
Definition
| 1. they may pass energy to chlorophyll A, as chlorophyll B does 2. they have a protective fxn - they absorb & dissipate excessive light energy that would otherwise damage chlorphyll |
|
|
Term
|
Definition
| a fixed quantity of energy |
|
|
Term
| why do the shorter wavelengths have greater energy? |
|
Definition
| they are able to absorb the specific amounts of energy in those photons |
|
|
Term
| what happens when a pigment absorbs a photon? |
|
Definition
| 1 of the pigment's electrons jumps to an energy level farther from the nucleus, where it has more potential energy |
|
|
Term
| what happens when isolated pigment molecules absorb light? |
|
Definition
| their excited electrons drop back down to the ground state in a billionth of a second, releasing their excess energy as heat |
|
|
Term
| 2 steps of demonstration of isolated pigments emitting light after absorbing photons |
|
Definition
| 1. when illuminated, chlorophyll emits photons that produce a reddish afterglow (called fluorescence); 2. IN FLUORESCENCE: a light-excited electron falls back to the ground state, emitting its energy as heat & light |
|
|
Term
| how does chlorophyll behave in its native habitat of the thylakoid memb.? |
|
Definition
| it passes its excited electron to a neighboring molecule |
|
|
Term
|
Definition
| consists of a number of light-harvesting complexes (ex. pigments & proteins, chlorophyll A&B, carotenoids) around a reaction center |
|
|
Term
|
Definition
| a protein complex that contains a chlorophyll A molecule and a molecule called the primary electron accepter |
|
|
Term
| what does the primary electron acceptor do |
|
Definition
| capture a light-excited electron from the rxn-center chlorophyll molecule & passes it to an electron transport chain |
|
|
Term
| pigments absorb ___ and pass the ____ from molecule to molecule until it reaches the ______ _______ |
|
Definition
| photons; energy; reaction center |
|
|
Term
|
Definition
| the chlorophyll A molecule of the rxn center is called P680 b/c the light it absorbs best is red light w/ a wavelength of 680nm |
|
|
Term
|
Definition
| the rxn center is called P700 b/c the light it absorbs best is red light w/ a wavelength of 700nm |
|
|
Term
| steps in the flow of electrons through both photosystems (ONLY PHOTOSYSTEM II) |
|
Definition
| 1. pigment absorbs a photon of light; energy is passed to other pigment mols & then to the rnxn center of photosystem2 where it excites an electron of chloropyll P680 to a higher energy level. 2. electron is captured by primary electron acceptor. 3. water enters chlorophyll P680 & is split; its electrons are supplied one by one to chlorophyll P680, replacing those lost to the primary electron acceptor; the oxygen atom combines w/ an oxygen from another split water molecule to form a molecule of O2 |
|
|
Term
| steps in the flow of electrons through both photosystems (ONLY PHOTOSYSTEM I) |
|
Definition
| 4. excited electrons pass from photosystem2 to photosystem1 via an electron transport chain; the exergonic "fall" of electrons provides energy for synthesis of ATP. 5. MEANWHILE- photon excites an electron of chlorophyll b in the rnx center of photosystem1; primary electron acceptor captures the excited electron & an elctron from the bottom of the electron transport chain replaces the lost electron in chlorophyll p700. 6. the excited electron of photosystem1 is passed thru a short electron transport chain to NADP+, reducing it to NADPH |
|
|
Term
|
Definition
| the mechanism that generates ATP in a chloroplast; drives ATP synthesis using the potential energy of a concentration gradient of hydrogen across a membrane |
|
|
Term
| where are the two photosystems & electron transport chains located? |
|
Definition
| within the thylakoid membrane of a chloroplast |
|
|
Term
| the ____ of the concentration gradient drives ____ back across the membrane through ______ |
|
Definition
|
|
Term
| ATP synthase couples the flow of ____ to the _____ of ____ |
|
Definition
| H+; photophosphorylation; ATP |
|
|
Term
|
Definition
|
|
Term
|
Definition
| the production of ATP by chemiosmosis during the light reactions of photosynthesis |
|
|
Term
| how does photophosphorylation compare w/ oxidative phosphorylation? |
|
Definition
IN CELL REP: the high-energy electrons passed down the electron transport chain come from the oxidation of food molecules.
IN PHOTOSYNTHESIS: light energy is used to drive electrons to the top of the transport chain |
|
|
Term
| what is the FINAL electron acceptor in photosynthesis ? in cell rep? |
|
Definition
|
|
Term
| do electrons end up at a low energy level in H2O? instead, they _______ |
|
Definition
| no, they only do in respiration; are stored at a high state of potential energy in NADPH |
|
|
Term
| what are ATP & NADPH produced during the light rxns used for? |
|
Definition
| used for the calvin cycle |
|
|
Term
| what is the advantage of the light rxns producing NADPH & ATP on the stroma side of the thylakoid membrane? |
|
Definition
| the calvin cycle (which consumes NADPH & ATP) occurs in the stroma |
|
|
Term
| what are the inputs for the calvin cycle & where do they come from? |
|
Definition
| CO2 (from the air) and ATP & NADPH (generated by the light rxns) |
|
|
Term
| what does the calvin cycle construct? |
|
Definition
| an energy-rich, 3 Carbon sugar, glyceraldehyde-3-phosphate (G3P |
|
|
Term
| what can a plant cell use G3P for? |
|
Definition
| to make glucose & other organic molecules needed |
|
|
Term
| what is the starting material (thing that is regenerated as process occurs)in the calvin cycle? |
|
Definition
| ribulose biphosphate (RuBP) |
|
|
Term
| NAME of steps of calvin cycle |
|
Definition
| 1. carbon fixation; 2. reduction; 3. release of one molecule of G3P; 4. rengeneration of RuBP |
|
|
Term
| steps in the calvin cycle |
|
Definition
| 1. the enzyme rubisco attaches CO2 to RuBP; 2. NADPH reduces the organic acid 3GPA to G3P w/ assistance of ATP. to make a molecule of G3P - the cycle must incorporate the carbon atoms from the 3 molecules of CO2; 3. for every 3 CO2 molecules fixed, 1 G3P molecule leaves the cycle as product & the remaining 5 G3P molecules are rearranged; 4. using energy from ATP, to regenerate 3 molecules of RuBP |
|
|
Term
| to synthesize one glucose of molecule, the calvin cycle must turn six times. in doing so, it uses ____ molecules of CO2, ____ molecules of ATP, and ____ molecules of NADPH |
|
Definition
|
|
Term
| how do plants stockpile their excess sugar? |
|
Definition
| as starch, storing it in the roots, tubers & fruits |
|
|
Term
| what is the ultimate source of all the food we eat & oxygen we breathe? |
|
Definition
|
|
Term
| explain why a poison that inhibits an enzyme of the calvin cycle will also inhibit the light rxns? |
|
Definition
| the light rnxs require ADP & NADP+, which are not recycled from ATP & NADPH when the calvin cycle stops |
|
|
Term
| C3 plants & why that is their name |
|
Definition
| plants in which the calvin cycle uses CO2 directly from the air; b/c the first organic compound produced is the 3-carbon compound (3-PGA) |
|
|
Term
|
Definition
| soybeans, oats, wheat, & rice |
|
|
Term
| what problem do farmers face w/ C3 plants? |
|
Definition
| dry weather can reduce the rate of photosynthesis & decrease crop productivity |
|
|
Term
| what does closing the stomata do ? (2 things) |
|
Definition
| 1. reduces water loss; 2. prevents CO2 from entering the leaf & O2 from leaving |
|
|
Term
| what is a result of the stomata closing? |
|
Definition
| CO2 levels get low while O2 from the light rxns build up. when this happens, rubisco adds O2 instead of CO2 to RuBP. a 2-carbon product of this rxn is then broken down by the cell to CO2 and H2O. this process is called photorespiration |
|
|
Term
|
Definition
| the breakdown of a 2-carbon product by the cell to CO2 and H2O. this rxn yields no sugar & no ATP |
|
|
Term
|
Definition
| plants that have a special adaptations that prevents photorespiration |
|
|
Term
| how does a C4 plant work? |
|
Definition
| when weather is hot & dry, it keeps stomata closed (which conserves water) & at the same time, it continues making sugar by photosynthesis. a C4 plant has an enzyme that first fixes carbon into a 4C (4 carbon) compound & w/ a high affinity for CO2 & can continue to fix carbon even when the CO2 concentration in the leaf is low. |
|
|
Term
| what does the 4C compound do? |
|
Definition
| transfers CO2 to nearby cells (bundle-sheath cells_ which are packed around the veins of the leaf. the CO2 concentration in these cells remains high enough for the calvin cycle to make sugars & avoid photorespiration |
|
|
Term
|
Definition
|
|
Term
|
Definition
| species adapted to VERY dry climates; converses water by opening stomata & admits CO2 only at night |
|
|
Term
|
Definition
| when CO2 enters the leaves, it is fixed in a a 4C compound. the 4C banks CO2 @ night & releases it to the calvin cycle in the day |
|
|
Term
|
Definition
| crassulacean acid metabolism |
|
|
Term
|
Definition
| C4 : carbon fixation & calvin cycle occur in different types of cells; CAM : these processes occur in the same cells, but @ different times |
|
|
Term
| how does a greenhouse work? |
|
Definition
| glass/plastic walls allow solar radiation to pass through ; sunlight heats soil which in turn warms up their ; walls trap the warm air, raising the temp inside |
|
|
Term
|
Definition
| sunlight warms earths surface, which radiates heat to the atmosphere. CO2 & other greenhouse gases absorb & radiate some heat back to earth |
|
|
Term
| what does the ozone layer do? |
|
Definition
| filters out most of the damaging UV |
|
|
Term
| examples of natural greenhouse gases vs synthetics |
|
Definition
| NATURAL: water vapor, CO2 & methane (CH4. SYNTHETIC: chlorofluorocarbons (CFCs) |
|
|
Term
| how do most fixed carbon return to the atmosphere? & if not? |
|
Definition
| via cellular respiration, the axn of decomposers, & fires. if not, it remains locked in large tracts of forests & undecomposed organisms |
|
|
Term
| amt of carbon dioxide before 1850 vs now |
|
Definition
| before: 0.03% of the air we breathe, now it is about 30% due to the combustion of carbon-based fossil fuels such as coal, oil & gasoline |
|
|
Term
|
Definition
| increasing concentrations of greenhouse gases - a slow but steady rise in Earth's surface temperature |
|
|
Term
| what happens are forests are cleared & agriculture and population growth increase the demand for fossil fuels? |
|
Definition
| CO2 levels will continue to rise |
|
|
Term
|
Definition
| high in the atmosphere, it is converted to ozone (O3) which plays an impt role for life on earth |
|
|
Term
| what does the ozone layer do |
|
Definition
| shields the earth's surface from powerful UV radiation that comes from the sun |
|
|
Term
|
Definition
| forms when high energy solar radiation breaks apart O2 mols & frees oxygen atoms. then it reacts w/ unbroken O2 molecules. ozone is continuously forming by the action of sunlight in the atmosphere |
|
|
Term
|
Definition
| when they react w/ other chemical compounds that are naturally present in the atmosphere. humans have disrupted that balance by releasing certain industrial chemicals that hasten this destruction |
|
|
Term
| name of scientist who studies ozone |
|
Definition
|
|
Term
| why do CFS make it up to the ozone? |
|
Definition
| they are very stable compounds |
|
|
Term
| what happens when CFCs reach the ozone? |
|
Definition
| solar radiation converts them to very reactive chemicals called free radicals, which then destroy the ozone |
|
|
Term
| where is the "ozone hole" (area where there is a drastic depletion of the ozone layer) |
|
Definition
|
|
Term
|
Definition
| international agreement to completely phase out the use of CFC production in 1996 |
|
|
Term
| when does the thinning of the ozone layer occur in the ozone hole? |
|
Definition
|
|
