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74 Cards in this Set
- Front
- Back
Heterotrophs |
Survived on nutrients from the environment |
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Autotrophs |
Manufacture organic nutrients from CO2 and H2S |
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_________ of complex molecules from CO2 requires a large input of energy |
Synthesis |
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Chemoautotrophs |
Use energy from inorganic molecules |
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Photoautotrophs |
Use radiant energy to make organic molecules |
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Photosynthesis |
Converts energy from sunlight into chemical energy stored in carbohydrates |
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Low energy electrons are removed from a _____ molecule |
Donor |
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First photoautotrophs used ___ as electron source |
H2S |
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Cyanobacteria used electrons from to produce _____ as a waste product |
Water |
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Photosynthesis in eukaryotes takes place in the __________ |
Chloroplast |
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Chloroplast |
A cytoplasmic organelle. |
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Chloroplasts have a double _________ |
Membrane |
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The outer membrane of chloroplast is ________ to large molecules |
Permeable |
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The inner membrane contains ________, __________, and _____________________ |
light-absorbing pigment electron carriers ATP-synthesizing enzymes |
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The inner membrane of a chloroplast is folded into ________ arranged in stacks called _______ |
flattened sacs (thylakoids) grana |
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Chloroplasts are self-replicating organelles containing their own ___ |
DNA |
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Thylakoid membranes contain a large percentage of glycolipids, which make the membrance highly fluid for ________________ |
Diffusion of proteins complexes |
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Photosynthesis is a redox reaction transferring an electron from ______ to _______ |
Water to Carbon Dioxide |
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Photosynthesis oxidizes ______ to ________ |
Water to Oxygen |
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Respiration reduces ______ to form ______ |
Oxygen to form water |
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Respiration removes high energy electrons from reduced organic substrates to form ____ and _____ |
ATP and NADH |
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Photosynthesis uses low energy electrons to form ___ and ______, which are then used to reduce CO2 to carbohydrate |
ATP and NADPH |
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Light-dependent reactions (light reactions) |
Sunlight is absorbed, converting it into ATP and NADPH |
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Light-independent (dark reactions) |
Use the energy stored in ATP and NADPH to produce carbohydrate |
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Absorption of photons by a molecule makes them go from _____ to ______ |
ground state to excited state |
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Energy in the photon depends on the __________________ |
wavelength of light |
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Molecules absorb specific _______________ |
wavelengths of light |
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Photosynthetic Pigments |
Molecules that absorb light of particular wavelengths |
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Chlorophyll contains a ________________ that absorbs light and a ____________________ embedding it to the photosynthetic membrane |
porphyrin ring hydrophobic tail |
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The alternating single and double bonds along the porphyrin ring form a cloud making it a __________ system |
conjugated |
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Conjugated bond systems absorb energy of range of ___________ |
wavelengths |
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Besides chlorophyll, there are accessory pigments called __________ |
caratenoids |
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Carotenoids |
absorb light in the blue-green region of spectrum |
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Each Photosynthetic Unit contains |
several hundred chlorophyll molecules |
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The reaction-center chlorophyll |
transfers electrons to an electron acceptor |
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Pigments that do not participate directly in the conversion of light energy are responsible for light absorption called ________ pigments |
antenna |
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Two large pigment-protein complexes called ___________ act in series to raise electrons from H20 to NADP+ |
photosystems |
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Photosystems II (PSII) |
Boosts electrons from below energy level of water to a midpoint |
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Photosystem I (PSI) |
Boosts electrons to a level above NADP+ |
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The reaction center of Photosystem II is referred to as ______ |
P680 |
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The reaction center of Photosystem I is referred to as ______ |
P700 |
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Electrons are transferred to a ____________________________ |
Primary electron acceptor |
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The flow of electrons from H20 to NADP+ is refereed to as the ____________ |
Z scheme |
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Photosystem II uses absorbed light energy to remove ________ and generate a _______________ |
electrons proton gradient |
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Two proteins, D1 and D2, bind the P680 chlorophyll and perform reactions to ________________ |
oxidize H20 |
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Light is harvested by a pigment-protein complex called __________________ |
light-harvesting complex II (LHCII) |
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Harvested energy is passed from LHCII to ___________________________ within PSII |
inner-antenna molecules |
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Excited P680 transfers energy to an electron acceptor generating ______ and _______ |
P680+ and Pheo- |
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P680+ and Pheo- are transferred to opposite sides of the thylakoid membrane where Pheo- passes an electron to _________________ |
Plastiquinone (PQ) |
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Plastiquinone (PQ) passes the electron to __________, then moved to the ___________ of the membrane |
Another PQ stromal side |
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The Flow of Electron from Water to PSII |
The redox potential of P680+ pulls electrons from water (photolysis) Formation of O2 requires four electrons from H20 Four electrons required to form O2 are transferred in cycles through P680+ to four Mn ions and one Ca ion that form the oxygen-evolving complex Protons produced in photolysis are retained in the thylakoid lumen Oxygen produced is released as a waste product into the environment |
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From PSII to PSI |
Production of O2 leads to formation of 2 molecules of PQH2 Reduced PQH2 then diffuses through thylakoid membrane and binds cyochrome b6f and releases protons the lumen of thylakoid Electrons from cytochrome b6f are passed to another carrier plastocyanin Plastocyanin transfers electrons to P700+ |
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PSI Operations: The production of NADPH |
The PSI consists of a reaction core center of 12–14 different polypeptides and a complex of protein-bound pigments called LHCI.
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Photosynthetic Electron Transport |
For every 8 photons absorbed: 2H20 + 2NADP+ => O2 + 2NADPH
Electron transport also produces a proton gradient across the thylakoid membrane |
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The machinery for ATP synthesis in a chloroplast is similar to that of ________________________ |
mitochondrial enzymes |
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The ATP synthase consists of a _____ and a ______ |
head (CF1) base (CF0) |
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The CF1 heads project outward into the stroma, keeping with the orientation of the _________________ |
proton gradient |
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Protons move into the lumen through the CF0 base of the _______ |
synthase |
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The movement of protons during photo-synthesis does not create a significant change in the membrane potential since other ions are ______________________________ |
transported simultaneously |
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The movement of electrons during the formation of oxygen is called __________________________ because the ions move in a linear path |
noncyclic photophosphorylation |
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Cyclic photophosphorylation is carried out by PSI __________ of PSII |
independently |
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C_3 plants |
Plants that produce a 3 carbon intermediate as the first compound to be identified during carbon dioxide fixation |
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The condensation of RuBP and the splitting of the 6 carbon molecule are catalyzed by 1 enzyme: |
Rubisco (ribulose biphosphate carboxlase) |
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Calvin Cycle |
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Carbohydrate Synthesis in C_3 plants |
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Redox Control is light _______ |
dependent |
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Key enzymes of Calvin Cycle are only active when ________ and _________ are produced by photosynthesis |
ATP and NADP |
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Some electrons used to reduce NADP+ are transferred to thioredoxin, which are accepted to ________________________________________ |
reduce disulfide bridges (-S-S-) in selected Calvin Cycle enzymes |
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In the _______, thioredoxin reduction ceases and enzymes go back to oxidized state and are inactivated |
dark |
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Photorespiration |
uptake of O2 and release of CO2 |
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Glycolate produced during photorespiration is shuttled to the _________ |
peroxisome |
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Peroxisomal enzymes convert glycolate to glyoxylate and then glycine, resulting in the loss of ____ |
CO2 |
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C4 pathway involves the production of ____________________________, which then combines with CO2 to produce 4-carbon compounds oxaloacetate |
Phosphoenolpyruvate (PEP) |
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CAM plants |
Carry out light reactions and CO2 fixation at different times of the day using the enzyme PEP carboxylase |