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35 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Reaction that
-requires light indirectly -uses stored energy to convert(fix) CO2 into carbohydrates |
dark reaction
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Reaction that
-converts and stores energy in energy transfer molecules (ATP) |
light reaction
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define photophosphorylation
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-describes light dependent reactions
-use of light energy to phosphorylate a molecule( ie:ADP) |
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Which evolved first, cyclic or non-cyclic photophosphorylation
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cyclic
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The reaction center for cyclic photophosphorylation
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P700
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First and Last enzymes of the photosynthetic electron transport chain
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FeS is First
and PC (plastocyanin) is Last |
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Cyclic Photophosphorylation
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-Excited (e-) releases energy in stepwise manner
-ezymatically aided (electron transport chain) -released energy at (PQ->Cyt F) phosphorylates (ADP-> ATP) -ground state electron returns to chlorophyll |
the steps of
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photosystem I (1) consists of
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- Antenna molecules
- P700 reaction center - Electron transport chain (FeS to Fd to FAD) |
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Non cyclic photophosphorylation
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-P700 (e-) leaves transport chain at Fd(ferredoxin)
-is passed to FAD -> NADP , energy released here makes ADP-> ATP -NADP red. acts as electron donor in the reduction of CO2 to carbohydrate (carbon fixation) -P680 (e-) fills electron holes in P700 |
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electron holes
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Electron deficit in photosystem I caused by carbon fixation, that is corrected by addition of (e-) from H2O
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Photosystem II(2) consists of
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- antenna molecules
- P680 reaction center - electron transport molecules |
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H20 's role with P680
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- passes (e-) through enzyme Z to P680
- forms 02 and 4H+ |
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Can replace H2O in photosynthesis
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- strong electron donors
- ie: H2S - gives off sulfer not O2 as a product |
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Chloroplast structure
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- inner membrane : smooth and flat, shaped to outer membrane
- third membrane inside stroma forms flat interconnected compartments called thylakoids |
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Contents of Thylakoid
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antenna pigments, Electron Transport chains,
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stromal thylakoids vs grana
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stromal - loose in stroma, ribbon-like, high surface area to absorb CO2
grana - densely packed, low CO2 absorption , high photon absorption |
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Distribution of Charges in Chloroplasts
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- H+ accumulates in innermost compartment of chloroplast
- outer compartment ( stroma becomes negatively charged) |
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Entrance point for H+ into thylakoid interior / inner compartment
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PQ and Z
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when is the cyclic pathway favored by (e-)
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-NADP ox. is in short supply
-Greater need for ATP than NADP red. |
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(e-) that do not enter cyclic pathway make....
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NADP red.
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Utilizes H+ gradient in thylakoid membrane
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CF-1 complex
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Calvin Cycle
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- CO2 combines with 5-Carbon sugar RuBP forming unstable 6-C compound
-broken down into two 3-Carbon PGA - PGA phosphorylated by ATP and reduced by NADPred. - two 3-Carbon PGAL form - 5 of every 6 PGAL make RuBP and 1 combines with another to form 6-Carbon glucose |
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Rubisco ( RuBP carboxylase)
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-catalyzes carboxylation of RuBP->
favored when CO2 is high, continues Calvin cycle -catalyzes the oxidation of RuBP by O2-> favored when CO2 is low, or temperatures above normal, starts photorespiration |
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photorespiration
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- breaks down intermediate molecules from the calvin cycle
- produces CO2 |
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funtion of cuticle and epidermis
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-cuticle covers epidermis
-epidermis protects internal tissues, protect from excessive water loss, from invasion of fungi & from mechanical injury |
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mesophyll
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-region between upper and lower epidermis
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stomata
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-holes in epidermis that open to atmosphere outside of the leaf
-size controlled by guard cells |
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Vascular Bundle
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- veins in leaf
- act as transport pathway - contain xylem and phloem - |
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Kranz anatomy - C4 plants
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-ringlike arrangement of phosynthetic cells ( contain enlarged chloroplasts) around leaf veins of C4 plants
-these cells accumulate starch in light -reduced number of chloroplasts, and greater number of grana in spongy mesohpyll |
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palisade mesophyll and spongy mesophyll
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palisade - upper,vertically arranged, cylindrical shaped
spongy- lower, irregular shaped |
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Location of Kranz/C4 plants
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High temperature, intense light, when stomatal closure results in low CO2 and high O2 inside of leaf
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C4 photosynthesis
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-CO2 combines with 3-Carbon PEP -> forms 4-Carbon compound
-responsible enzyme cannot create O2 and is not inhibited by it |
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Hatch-Slack pathway - C4 photosynthesis
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-CO2 combines with PEP, forms 4-Carbon compound
-reduced by NADPred. -passes into bundle sheath cell -oxidized by NADPox. -Form 3-C compound and CO2 -3-C compound returns to mesophyll to form PEP -CO2 enters Calvin Cycle |
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Crassulacean Acid Metabolism (CAM)
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- succulent plants that store water in fleshy leaves
- close stomata during day, open them at night - necessary CO2 stored as malic acid and isocitric acid - release in cells during day |
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CAM vs C4
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C4- anatomical seperation of CO2 fixation
CAM - temporary seperation |
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