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160 Cards in this Set
- Front
- Back
autotroph |
uses inorganic substances such as water and carbon dioxide to produce organic compounds - makes their own food
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heterotroph |
organism that obtains carbon by consuming preexisting organic molecules -consumes other organisms |
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organisms that can produce their own food |
underlie every ecosystem on earth |
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photosyntheis |
process by which plants, algae, and some microbes harness solar energy and convert it into chemical energy |
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photosynthesis uses |
water and releases oxygen gas as a byproduct |
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photosyntheisis is important beause |
-animals, fungi and other consumers eat the leaves, stems, roots, flowers, nectar, fruits, and seeds of the worlds autotrophs -provides food for the plan -raw materials and oxygen that most heterotrophs need |
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this takes light energy to assemble co2 into glucose |
photosynthesis |
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uses: carbon dioxide, water, and sunlight |
makes: glucose and O2(oxygen) |
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photosynthetic pigments |
capture sunlight |
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electromagnetic spectrum |
range of possible frequencies of radiation - contains discrete packets of kinetic enery called photons |
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photon |
a discrete packet of kinetic energy in ll electromagnetic radiation |
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wavelength of a photon |
the distance it moves during a complete vibration
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the shorter the wavelength |
the more energy it contains |
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the longer the wavelength |
the less energy it contains |
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most abundant pigment molecule that captures light enery is |
chlorophyll a |
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cholorophyll a |
green photosynthetic pigment in plants, algae, and cyanobacteria |
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green photosynthetic pigment in plants, algae, and cyanobacteria |
chlorophyll a |
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accesory pigments |
energy capturing pigment molecules other than chlorophyll a |
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energy capturing pigment molecules other than chlorophyll a |
accessory pigments |
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chlorophyll b and carotenoids are |
accesory pigments in plants |
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chlorophyll a is |
most abundent pigment molecule in plant cells |
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chlorophylls a and b absorb__________ wavelengths |
red and blue |
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plants appear green because |
they reflect green light |
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carotenoids |
reflect longer wavelengths of light, so they appear red, orange, or yellow ( carrots, tomatoes, lobster shells) |
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only ______ is useful in photosynthesis |
absorbed light |
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______ absorb wavelengths that chlorophyll a cannot |
accesory pigments |
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visible light is in the _________ of the electromagnetic spectrum |
middle range |
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wavelentghs in visible light: shortest to largest |
violet, blue, cyan, green, yellow, orange, red |
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plants benefit by having multipe types of pigments because they can then |
abosrb more wavelengths |
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chlorophyll molecules reflect green and yellow wavelenths of light and absorb the other wavelengths |
each pigment absorbs some wavelentghs of light and reflects others |
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chloroplasts are the site of |
photosynthesis |
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in plants, _____ are the main organs of photosynthesis |
leaves |
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plants must exchange CO2 and O2 with the atmosphere through |
stomata( stoma) |
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stoma/stomata |
tiny openings in the epidermis of a leaf or stem -tiny dent in membrane walls like seen in telescope of lab |
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tiny opening in the epidermis of a leaf or stem |
stoma |
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the collective term for these internal cells of a leaf where most photosynthesis occurs |
mesophyll |
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meso |
middle |
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phyll |
leaf |
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mesophyll cells contain |
bbundant chloroplasts |
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stroma |
gelatinous fluid containing ribosomes, DNA, and enzymes |
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gelatinous fluid containing ribosomes, DNA, and enzymes |
stroma |
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stoma |
leaf pore |
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in the stroma of each chloroplasts are |
between 10 to 100 gana |
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grana( singular: granium) |
-are in stroma of each chloroplast -composed of thylakoids |
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thylakoid |
consists of a membrane studded with photosynthetic pigments and enclosing a volume called the thylakoid space |
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tissue inside a leaf is called |
mesophyll |
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each mesophyll cell contains multiple |
chloroplasts |
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a chloroplast contains |
light harvesting pigments |
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light harvesting pigments in chloroplast are embedded in |
stacks of thylakoid membranes that make up each granum |
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pigments and proteins that particpate in photosynthesis are groupd into __________ in the thylakoid membrane |
photosystems |
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photosystem |
consists of chlorophyll a aggregated with other pigment molecules and the proteins that anchor the entire complex in the membrane |
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although all pigment molecules absorb light energy only |
one chlorophyll a molecule per photosystem actually uses the energy in photosynthetic reactions |
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chlorophyll a molecule and its associated proteins |
the photosystems reaction center |
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reaction center of a photosystem |
is chlorophyll a molecule and its associated proteins |
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all other pigment molecules in the photosystem are called |
antenna pigments |
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antenna pigments |
- are all other pigment molecules int eh photosystems -capture photon energy and funnel it to the reaction center |
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relationship among the chloroplast, stroma, grana, and thylakoid |
thylakoids make up a granum, grana are found in stroma, stroma is the fluid part in the inside of chloroplasts double membrane |
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antenna pigments pass energy on to the reaction center |
reaction center then participates in photosynthetic reactions |
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inside the chloroplast, photosynthesis occurs in two stages= |
light reactions carbon reactions |
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______ convert solar energy to chemical energy |
light reactions |
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light reactions |
photo- |
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in thylakoid membranes, pigment molecules in two linked photosystems capture kinetic energy from photons and store it as |
potential energy in the chemical bonds of two molecules: ATP and NADPH |
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ATP |
-energy rich product of light reactions a nucleotide that stores potential energy in the covalent bonds between its phosphate groups - forms when a phosphate group is added to ADP |
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NADPH |
-energy rich product of light reactions -a molecule that carries paris of enerized electrons... in photosynthesis these electrons come from chlorophyll molecules |
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O2 is released as a byproduct because |
once the light reactions are underway, chlorophyll in turn, replaes its lost electrons by splitting water molecules |
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ATP |
energy |
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NADPH |
loaded electron carriers |
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_________ use ATP and the high energy electrons in NADPH to reduce CO2 to glucose molecules |
carbon reactions |
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carbon reactions |
-synthesis |
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ATP and NADPH come from the |
light reactions |
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CO2 comes from |
the atmosphere |
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photosynthesis strips electrons from the oxygen atoms in H2O, these electrons then reduce the |
carbon in CO2 |
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moving electrons from oxygen to carbon requires energy because |
oxygen atoms attract electrons more strongly than do carbon atoms |
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energy source for moving electrons from oxygen to carbon is |
light |
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in carbon reactions |
co2 from the atmopshere enters the leaf and diffuses into a mesophyll cell and across the chloroplast membrane into the stroma where the carbon reactions occur |
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in light reactions |
pigment molecules between two linked photosystems in thylakoid membranes capture kinetic energy from photons and store it as potnential energy in the chemical bonds of either ATP or NADPH |
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in light reactions |
pigment molecules capture sunglight energy and transfer it to molecules of ATP and NADPH |
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carbon reactions use _______ to build glucose out of carbon dioxide |
ATP and NADPH |
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H20 and light go in to ___________ and produce O2 (oxygen) as a byproduct, also produce ATP and NADPH |
light reactions |
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co2 goes into ______ and uses ATP and NADPH to produce glucose |
carbon reactions |
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_________ reactions begin photosynthesis |
light |
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pigments and proteins of the chlorolasts thylakoid membranes are organized into |
photosystems |
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the thylakoid memranes contain two types of photosystems |
I and II - electron transport chain connects the two photosystems |
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what connects the two photosystems |
electron transport chain |
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a group of proteins that shuttle electrons from carrier to carrier, releasing energy with each step |
electron transport chain |
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the electron transport chain that links photosystems I and II |
stores potential energy used in ATP synsthesis |
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second electron transport chain extending from photosystem I ends with the production of |
NADPH |
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order of light reactions |
photosystem II, electron transport chain, photosystem I, electron transport chain, production of NADPH |
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in light reactions |
chlorophyll molecules in photosystem II transfer light energy to electrons, electrons are stripped form water moelcules, releasing oxygen, the energized electrons pass to photosystem I via an electron transport chain. Each transfer releases energy that is used to pump hydrogen ions into the thyakoid space, the resulting hydrogen gradient is used to genereate ATP, in photosystem I the electrons absorb more light energy and are passed to NADP creating NADPH |
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photosystem II produces |
ATP |
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photosynthesis begins in |
-the cluster of pigment molecules of photosystem II -these pigments absorb light and transfer the energy to a chlorophyll a reaction center, where it boosts two electrons to a higher energy level |
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the excited electrons in photosystem II are |
ejected from this chlorophyll a molecule and grabbed by the first protein in the electron transport chain that links the two photosystems |
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how does chlorophyll a molecule replace the two electrons ejected and sent down the transport chain? |
H2O, which dontes two electrons when it splits into oxygen gas and two protons(H+) chlorophyll a picks up the electrons, and O2 is a waste product that the plant releases to the environment |
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chloroplast uses the potential energy in the electrons to |
create a proton gradient |
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as the electrons pass along the elctron transport chain the energy they lose |
drives the active transport of protons from the stroma into the thylakoid space |
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the proton gradient between the stroma and the inside of the thylakoid represents |
a form of potential energy |
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ATP synthase |
enzyme complex -transforms the protons gradients protnetial energy into chemical energy in the from of ATP |
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in atp synthase |
-a channel in atp synthase allows protons trapped inside the thylakoid space to return to the chloroplasts stroma -as the gradient dissipates, energy is released -the atp synthase enzyme uses this energy to add phosphate to adpm genereating atp |
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photosystem I produces |
NADPH |
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ATP is produced in |
photosystem II |
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in photosystem I |
the electrons reduce a molecule of NADP+ to NADPH - this NADPH is the electron carrier that will reduce carvon dioxide in the carbon reactions, the ATP generated in photosystem II will provide the energy |
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events from beginning of photosystem II to he production of ATP |
pigments abosrb light and transfer the energy to a chlorophyll a reaction center where it boosts two electrons to a higher energy lvel. these two electrons are ejected from the chlorophyll a molecule and grabbed by the first protien in the electron transport chain. As the electrons pass along the electron transport chain, the energy they lose drives the active transport of protons from the stroma into the thylakoid space. The resulting proton gradiant represents a from of potential energy. ATP synthaze (enzyme complex) transforms the gradients potential energy into chemical energy in the form of ATP |
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carbon reactions produce |
carbohydrates |
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carbon reactions |
albin cycle |
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carbon reactions/ calvin cycle occurs in |
chloroplasts stroma |
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calvin cycle is |
the metabolic pathway that uses NADPH and ATP from the light reactions to assemble CO2 molecules into three carbon carbohydrate molecules |
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the metabolic pathway that uses NADPH and ATP from the light reactions to assemble CO2 molecules into three carbon carbohydrate molecules |
calvin cycle/ carbon reactions |
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first step of calvin cycle is |
carbon fixation- initial incorporation of carbon from CO2 into an organic compound |
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carbon fixation |
- first step of the carbon reactions - CO2 combines via rubisco with RuBP
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initial incorporation of carbon from CO2 into an organic compound |
carbon fixation |
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ribulose biphosphate(RuBP) |
five carbon sugar with two phosphate groups |
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rubisco |
an enzyme that catalyzes carbon fixation |
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carbon fixation combination of CO2 and RuBP |
turns into PGA then PGAL then rearranged to form additional RuBP. Cell can use PGAL to build larger carbs such as glucose and sucrose |
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plants cells use about ___ of the glucose as fuel for their own cellular respiration |
half |
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_______ are the building blocks of the cellulose wall that surrounds every plant cell |
glucose molecules |
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excess glucose than it immediatiely needs for respiration or buildig cell walls is stored as |
starch |
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what happens in carbon reactions |
CO2 combines with RuBP and is catalyzed by rubisco then turns into PGA then PGAL then rearranged to form additional RuBP |
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in calvin cycle |
1.carbon dioxide is added to RuBP, creating an unstable molecule 2.the unstable intermediate splits to form PGAL 3.PGAL molecules are combined to form glucose which is used to form starch, sucrose, and other organic molecules 4.RuBP is regnereated by arranging the remainng molecules 5.cycle repeats |
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roles of CO2, ATP, and NADPH in the calvin cycle |
co2- combines with RuBP to create an unstable balance and initiate the carbon cycle ATP and NADPH- power calvin cycle |
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calvin cycle is also known as the |
C3 pathway |
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C3 pathway |
three carbon molecule, PGA, is the first stable compound in the pathway
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all plants use the calvin cycle |
true |
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C3 plants use |
only c3 pathway to fix carbon from CO2 |
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__% of plants are c3 |
95% |
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c3 photosnthesis is a succesful adaptation but it does have a weakness |
inefficiency |
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photosysnthesis has a theoretical efficiency rate of |
30% |
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photosrespiration |
a series of reactions that begin when the rubisco enzyme uses O2 instead of CO2 as a substrate - so plant loses co2 tat it has already fixed, wasting both ATP and NADPH |
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photorespiration is most likely in |
hot, dry climates |
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under what conditions does photorespiration become much more likely and photosynthetic effieciency plumets |
when the plant closes its stomata, CO2 supplies in the leaves run low while O2 builds up |
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in hot climates plants that minimize photorespiration may therefore have a |
significant competitive adcantage |
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one way to imporve efficiency in photosynthesis is to |
ensure that rubisco always encounters high CO2 concnetrations |
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C4 and CAM pathways are |
two adaptations to imporve effiency of phototsynthesis through making sure rubisco always encounters high CO2 concentrations |
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C4 cells |
-physically separate the light reactions and the carbon reactions into different cells - light reactions occur in mosphyll cell, as does a carbon fixation reaction called the C4 pathways |
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C4 pathway |
co2 combines with a three carbon molecule to orm a four carbon compound - this molecule then moves into adjacent bundle sheath cells that surround the leaf veins -co2 is liberated inside these cells, where the calvin cycle fixes the carbon a second time by the C3 pathway |
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bundle sheath cells |
cells that surround the leaf veins -are not exposed direcly to atmospheric O2 -making rubisco in bundle sheath ells more likely to bind CO2 instead of O2, reducint photorespiration -the three cabon molecule returns to the meophyll to pick up another O2 at the cost of two TP molecules |
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__% of plants use the C4 pathway and those that do are flowring plants growing in hotm open enviornments( crabgrass, sugar cane, and corn) |
1 |
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another way to improve efficiency of phoosynthesis by rubisco having high CO2 concentrations is |
CAM pathway |
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CAM pathway |
crassulacean acid metabolism -3-4% of plant species -pineapple and cacti
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In cam pathway plants |
-open their stomata to fix CO2 only at night when the temperature drops and the humidity rises -CO2 diffuses in -mosophyll cells incorporate the CO2 into a four carbon compound which they store in large vacuoles -stomata close during the heat of the day, but the stored molecule moves from the vacuole to a chloroplast and releases its CO2. -the chloroplast then fixes the CO2 in the calvin cycle |
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the CAM pathway reduces photorespiation by |
generating high CO2 concentrations inside chloroplasts |
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all cam plants are adapted to |
dry habitats |
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in cool environments _____ plants cannot compete with _____ plants |
CAM, C3 |
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CAM plants stomata are only open at |
night... therefore they have much less carbon available to their cells for growth and reprodcution |
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calvin cycle is also called the C3 pathways becasue |
three carbon molecule, PGA, is the first stble compound int the pathway |
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how does photorespiration counter photosynthesis |
the rubisco enzyme uses O2 instead of CO2 as a substrate, so plant loss CO2 wasting both ATP and NADPH |
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describe how a C4 plant minimizes photorespiration |
-co2 combines with a three carbon molecule= C4 -C4 then moves into bundle sheath cells that surround the leafs veins -co2 is then liberated inside these cells where the calvin cycle fixes the carbon a second time by the C33 pathway |
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how is the CAM pathway like the C4 metabolism and how is it different |
CAM pathway is like C4 metabolism in that they both take on different forms to counter the effects of photorespiration and they both result in the calvin cycle fixing the carbon, yet the CAM pathway plants only open their stomata at night so they get high humidity and low temperatures |
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c3 plant |
co2 goes into mesphyll cell turns into 4 carbon molecule then into bundle sheath cell where it goes through calvin cycle and comes out glucose |
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CAM plant |
co2 goes into mesophyll cell at night turns into 4 carbon molecules then into calvin cycle and out glucose at day |
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limitation of c3 plant |
photorespiration |
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limitation of c4 plant |
atp cost |
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limitation of CAM plant |
reduced carbon availability |
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how c4 plants avoid photorespiration |
light reactions and carbon reactions occur in separate cells |
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how CAM plans avoid photorespiration |
co2 is absorved at night; light reactions and carbon reactions occur during the day |
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c3 plants habitat |
cool, moist |
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c4 plant habitat |
hot, dry |
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cam plant habitat |
hot, dry |
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percent of c3 species |
95% |
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percent of c4 species |
1% |
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percent of cam species |
3-4% |