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152 Cards in this Set
- Front
- Back
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Solute potential of soil (numbers) |
-0.02 MPa (negligible) -0.2 MPa in saline soil |
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Pressure potential for Soil (numbers) |
Wet soil- close to 0 As soil drys, becomes more negative |
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How does water move through soil |
Bulk flow in response to pressure gradient |
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How does the water move? (what type of potential)
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Soil- pressure potential Across root- water potential In xylem- pressure potential Leaf air spaces- water vapor concentration |
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Root Hairs (definition) |
Filamentous outgrowths of root epidermal cells that increase the surface area of the root |
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Explain the picture |
Mature regions of the root are less permeable. This allows most of the water uptake to occur in new growth in new areas! |
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Pathways from epidermis to endodermis |
Apoplast Symplast Transmemebrane |
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Apoplast (definition, function) |
water moves through cell walls and extracellular spaces w/o crossing any membranes as it travels to the root cortex |
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Symplast (definition, function) |
Water travels across root cortex via plasmodesmata in the cell |
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Transmembrane pathway (definition, function) |
water enters a cell on one side and exits the cell on other Crosses plasma membrane twice in each cell. May also cross tonoplast |
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Tonoplast (definition) |
Membrane that surrounds vacuole |
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Caspian strip (definition, function) |
Hydrophobic strip between cell walls of endodermis. Forces water to go through endodermis membranes and aquaporins |
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Root pressure (definition) |
Positive hydrostatic pressure in the xylem of roots. Caused by build up of solutes and low transpiration eg- night time and dew drops |
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Guttation (definition) |
Exudation of liquid from leaves due to positive root pressure |
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Xylem Parts (types, function) |
Tracheids- elongated hollow dead cells with highly lignified walls Vessel Elements- Dead cells, shorter and wider than tracheas, have perforation plates at each end of the cell. Stack and form a longer tube called a vessel |
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Conifer Xylem pit |
A- Margo B- Torus C- Pit Cavity |
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Other Vascular Plants |
A- Secondary cell walls B- Pit Membrane C- Pit Cavity D- Primary cell walls |
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Pressure-driven Bulk Flow (function in plant) |
Responsible for long-distance transport of water in xylem Independent of solute concentration gradients Xylem provides low resistance pathway for water |
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Cohesion-tension theory of sap ascent (explain ESSAY QUESTION) |
As water evaporates, it pulls more water up to the top of the plant. Requires cohesive properties of water to sustain high tension in the xylem water columns |
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How much pressure to move water to the top of a tree? (number) |
2MPa |
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Xylem cavitation and how the plant minimizes the problem |
-The loss of tension in the xylem due to the formation of a gas bubble -positive pressure can sometimes break bubble -Water flows around bubble and new xylem forms |
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Major factors for transpiration |
1- difference in water vapor concentration between the leaf air spaces and external bulk air 2-Diffusional resistance (r) of this pathway |
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Diffusional Resistance (r) |
Two components- leaf stomatal resistance and boundary layer resistance |
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Leaf stomatal resistance |
associated with diffusion through stomatal pore resistance of CO2 diffusion through stomatal pore |
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Leaf boundary layer resistance |
resistance to diffusion of water vapor due to layer of unstirred air next to leaf surface |
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What is the driving force for transpiration? |
-Difference in water vapor concentration! -Must be lower outside of cell than inside cell so water moves out |
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Stomata- function |
-Leaf transpiration -Changes in stomatal resistance important for water loss regulation -Temporal regulation -When water is not abundant, stomata will close to retain water |
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Abscisic Acid (Definition, function) |
Hormone that helps control opening and closing of stomata pores Works with specialized epidermal cells and guard cells |
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Stomatal Complex
(parts) |
Guard cells, subsidiary cells, and pore Guard cells photosynthesize to create energy for opening Subsidiary cells are specialized epidermal cells |
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Grass-Like Stomata A-epidermal cells B- Radially arranged cellulose microfibrils C- Guard Cells D- Pore E- Subsidiary Cells F- Stomatal complex |
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Kidney shaped stoma (dicots and non-grass monocots) A- epidermal cells B- Radially arranged cellulose microfibrils C- Guard cells D- Pore Subsidiary cells are often absent! |
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Transpiration Ratio |
Amount of H2O transpired divided by amount of CO2 assimilated by photosynthesis C3 plants- 400 C4 Plants- 150 CAM Plants- 50 |
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Water Use Efficiency |
1/Transpiration Ratio Bigger number=more efficient plant C3 plants- 0.0025 C4 plants- 0.006 CAM Plants- 0.02 |
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What causes large ratio of H2O efflux to CO2 influx? |
Concentration gradient driving H2O loss is 50 times larger CO2 diffuses 1.6 times slower through air CO2 must cross membranes before assimilation |
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Essential Element (definition) |
Component in the structure or metabolism of a plant, or whose absence causes severe abnormalities in plant growth, development and reproduction |
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Macronutrients (definition, list) |
According to relative concentration Nitrogen, potassium, calcium, magnesium, phosphorus, sulfur, silicon |
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Micronutrients (definition, list) |
According to relative concentration Chlorine, iron, boron, manganese, sodium, zinc, copper, nickel and molybdenum |
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Classification by Biochemical function |
Group 1- carbon compounds Group 2-Energy storage or structural integrity Group 3-Ionic form nutrients Group 4-Redox reaction nutrients |
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Biochemical classification Group 1 (Definition, list) |
Carbon compounds N- amino acids, proteins, etc S- amino acids, proteins, oils. Chlorophyll formation, develop and activate certain enzymes and vitamins |
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Biochemical Classification Group 2 (definition, list) |
Every storage or structural integrity P-Phospholipids and ATP Si-Cell wall B-Cel wall. Cell elongation and nucleic acid metabolism |
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Biochemical Classification Group 3 (definition, list) |
Ionic Form K+ Cofactor and cell turgor and cell electroneutrality Ca+ middle lamella of cell walls. Cofactor for hydrolysis of ATP and phospholipids. Messenger metabolic regulation Mg Chlorophyll molecule Cl- required for photosynthetic reaction involved in O2 evolution Zn alcohol dehydrogenase, and other ases Na+ Phosphoenolypyruvate regeneration in C4 and CAM plants |
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Biochemical Classification Group 4 (definition, list) |
Redox Reactions Fe- cytochromes and nonhdme iron proteins in photosynthesis. N2 fixation and respiration Mn- photosynthesis O2 evolution Cu- Ascorbic acid oxidase, helps with photosynthesis Ni- constituent of urease Mo- constituent of nitrogenase, nitrate reductase and xanthine dehydrogenase |
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Hoagland Solution (definition, use in experiments) |
Solution created for plant growth in systems. Provides all necessary nutrients for growth. Can be adjusted as needed |
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Iron chelation (how it happens) |
Iron bonds to DTPA with ionic forces to make it accessible to plants. Inside the plant it is chelated with organic compounds like citric acid
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Deficiency Symptoms |
Difficult to diagnose. occurs with improper nutrients. Mobile and immobile nutrients. |
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Mobile Elements (definition, list) |
Nitrogen, potassium, magnesium, phosphorus, chlorine, sodium, zinc, molybdenum Symptoms appear on older leaves first- move nutrients to new leaves |
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Immobile Elements (definition, list) |
Calcium, sulfur, iron, Boron, copper Symptoms appear on younger leaves first- nutrients can't move around plant |
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Soil analysis |
Chemical determination of nutrient content of soil sample from root zone |
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Three nutrient zones |
Deficiency, adequate, toxic Must reach critical concentration or plant does very poorly. Also hard to recover from toxicity |
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Explain the figure
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pH and availability of nutrient elements in soils Redbox is area where all the nutrients are available. pH between 5.5-6.5 is ideal for all nutrient uptake Fungi like acidic soils and bacteria like alkaline soils which is important for nutrient uptake |
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Mineralization |
Breakdown of organic compounds into nutrient elements by soil microorganisms |
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How do roots sense the environment? (list) |
Gravitropism (gravity), thigmotropism (touch), chemotropism (chemicals) and hydrotropism (water) |
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How many roots does a plant need? |
Not that many. They can sufficiently supply nutrients to a plant as long as there are nutrients to be found |
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Cation exchange (what and why?) |
Replacement of mineral cations adsorbed to the surface of a soil particle provides a nutrient reserve available to plant roots |
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Cation exchange capacity (CEC) |
Degree to which a soil can adsorb and exchange ions and depends on soil type Light colored sands- 3-5 men/100g soil Organic soils- 50-100 men/100g soil |
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Longitudinal section of the apical region of root (parts) |
Maturation zone- root hairs absorb water and solutes, xylem translocates water and solutes Elongation zone- 0.7-1.5 mm from apex, cells elongate rapidly Meristematic zone- cells divide in both directions (base and apex) |
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Mucigel |
Like gelatin. Helps protect root tip as it moves through dirt. Helps with nutrient absorption and microbes |
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Nutrient Depletion Zone |
Rate of nutrient uptake exceeds rate of replacement by bulk flow and diffusion |
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Arbuscular Mycorrhizal Symbiosis and land plant evolution |
AM symbiosis around for >400MYA Probably helped make the transition to land Not all plants can make this association |
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Ectomycorrhiza (definition) |
Outside the roots. Trees and shrubs. Doesn't penetrate cells, but can go between cells. Often gymnosperms Often woody plants |
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Endomycorrhiza (definition) |
Penetrates cells and goes intercellular Form arbuscules near vascular tissue |
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Arbuscular mycorrhizae (what is it) |
Arbusculum= small tree mycos= fungus Glomeromycota fungus 80% of land plants have it Obligate symbionts AM gives plants phosphate and nitrogen AM fungus gets ~20% of photosynthetic carbon |
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Arum-type AM |
Forms dichotomously (two) branched arbuscules Travels between cells in intercellular space |
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Paris-type AM |
Form coil-like branched arbuscules Travels between cells by piercing cell membranes |
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Development of AM Symbiosis |
Spore attaches to root- has enough carbon to germinate -will die without root Plants break down vacuole into small compartments so they can hold arbuscule |
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Label the AM Symbiosis |
A-vesicle B-arbuscules C-appressorium D-external hyphae E-spore |
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Label the arbuscule |
A-cortical cell B-plasma membrane C-peri-arbuscular membrane (proteins for nutrient exchange) D-peri-arbuscular space E-arbuscule cell wall A2- arbuscule membrane |
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Myc factor |
"i'm a friendly fungus" chemical causes calcium spiking in cell with changes gene expression to let AM in cell |
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Strigolactone |
Induce spore germination for fungus- good if its AM fungus Also causes germination of parasitic seeds, which is bad- seeds 'eavesdrop' on signal Increased production when soil nutrients are low, which causes more root growth |
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Hyphopodium |
Attaches fungus to root and prepares it for root penetration
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Formation of PPA |
Pre-penetration apparatus Breech in cytoplasm that is made of cytoskeleton pieces that guide the fungus into the cell |
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Fungal penetration (how it happens) |
Fungi hypha enter the PPA, which guides fungus toward inner cortex cells Fungus enters apoplast (area between cells near inner cortex) form PPA like structures in inner cortex cells and then make arbuscules |
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Explain what is happening? |
A- mineral nutrients P, N, Zn, and S are leaving the fungus and moving into the plant B- sugars, which provide carbon are leaving the plant and going to the fungus. There are proteins to help nutrients move across cell membranes |
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Efflux |
'flowing out' material leaving a cell |
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Phosphate transport in Mycorrhizal plants |
-Hyphae grow beyond P depletion zone and bring back P that the plant couldn't reach -Phosphate can enter the cell in two ways- plant from soil, or mycorrhizae from soil to plant -P is actively transported across the cell membrane in synport- protein that does this is ESSENTIAL for symbiosis |
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Explain the figure |
Initially strigolactone and salicylic acid increase. Salicylic acid is plant defense and strigolactone stimulates fungus development Then strigolactone and salicylic acid decrease and jasmonates increase. The plant doesn't need to cause germination or protect itself from the fungus, but jasmonates help protect the plant from insects |
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Explain the figure |
In plants with no AMF- parasitic plants grow, insects attack the roots and shoots, there are lots of diseases In plants with AMF- plant growth, repel insects at roots, stop parasitic plants, prime defenses against other nasty things. Plant attracts good insects. Also attract phloem feeders and fungal/viral biotrophs |
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Photosynthesis overall reaction |
6CO2+6H2O+light energy---> C6H12O6+6O2 |
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Nature of light |
Wave and particle Wavelength- distance between crests Frequency- number of wave crests Light is a photon Quantum is the energy of a photon |
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Amount of energy in a photon |
E=hv Energy= planck's constant x frequency |
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Electromagnetic spectrum |
Purple, blue, green, yellow, red 400----------------------------------700 |
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What happens when molecule absorbs a photon? |
molecule in ground state is raised to excited state with more energy. Will fall back to ground state after it passes energy to next molecule |
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Absorption spectrum of chlorophyll |
Absorbs in the purple and blue, and red reflects green |
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Label the chloroplast |
A- Grana lamella (stacked thylakoids) B- Thylakoid C- Stroma lamella D- Inter membrane space E- Outer envelope F- Stroma lamella G- Granum (stack of thylakoids) H- Thylakoid lumen I- Thylakoid J- Inner envelope |
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What is a pigment? (definition) |
substance that absorbs light Plants have a mixture of pigments to increase absorbed light |
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Chlorophyll |
Chlorophyll a and b most abundant in plant light absorption, energy transfer, electron transfer Chlorophyll a- has methyl group and magnesium Chlorophyll b- has aldehyde and magnesium |
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Explain the image |
A shows how the molecule drops energy levels. First heat is emitted, then light is emitted for the final drop to the ground state. Spectra absorption happens at the same place |
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Action spectrum (definition) |
Represents the magnitude of a response of a biological system to light as a function of wavelength |
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Antenna Complex (form, function, location in cell) |
Majority of pigments serve in it. Collect light and transfer energy to a reaction center complex, where redox reactions lead to long-term energy storage take place PSI and PSII |
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Reduction reaction (definition) |
gain of electrons, hydrogen or the loss of oxygen decrease charge of moledule |
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Oxidation reaction (definition) |
loss of electrons, hydrogens, or gain of oxygen increase charge of molecule |
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NAD+ and NADP+ (definition) |
NAD+ nicotinamide adenine dinucleotide NADP+ nicotinamide adenine dinucleotide phosphate Two strong oxidizing agents- oxidize materials they react with |
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NADP and NADPH (definition) |
two strong reducing agents, with give the hydrogens |
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Redox potential (definition) |
tendency to accept or donate electrons |
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Light/Thylakoid reactions (input, output, location) |
Input- H2O, NADP+, ADP Output- O2, NADPH, ATP In the thylakoid |
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Light-independent reactions (input, output, location) |
Input- ATP, NADPH, CO2 Output- ADP, NADP+, Carbohydrates In the stroma |
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Quantum Yield (definition) |
Number of photochemical products/ total number of quanta absorbed |
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Photosynthesis and red light (what types of red light?) |
Need both red and far red light photosynthesis works best when light is absorbed by chlorophyll, not accessory pigments |
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Describe image |
Z scheme of photosynthesis. -Red light is absorbed by PSII and produces a strong oxidant and a weak reductant -Far red light is absorbed by PSI and produces a weak oxidant and strong reductant -Strong oxidant from PSII oxidizes H2O, while strong reductant produced by PSI reduces NADP+ Light Reaction! |
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Explain the image |
-How energy flows through pigments to the reaction center -95-99% of photons absorbed by antenna pigments have their energy transferred to the reaction center -Pigments closer to the reaction center are lower in energy to create a energy gradient so it flows to the center |
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Fluorescence resonance energy transfer (definition) |
physical mechanism by which the excitation energy is transferred from one molecule to another |
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Photosystems I and II (location, connector, ratio) |
PSII is in grana lamellae and PSI is in the stroma lamellae and edges of grana lamellae Cytochrome b6f complex connects photosystems PSII to PSI ratio is usually 1.5:1 |
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Four major protein complexes in light reactions |
Photosystem 2, cytochrome b6f complex, photosystem 1, ATP synthase |
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Photosystem 2 reaction center (parts, proteins) |
Multisubunit pigment-protein Two complete reaction centers and some antenna complexes Core reaction center two membrane proteins D1 and D2 Primary donor chlorophyll, carotenoids, pheophytins, and plastoquinones are bound to D1 and D2 |
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PS2 Water oxidation (what, cofactor) |
PS2 oxidizes H2O and releases protons into lumen Occurs in Oxygen evolving complex Manganese is essential cofactor But we don't know why |
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Election acceptors from PS2 (pathway through cell) |
Pheophytin, a chlorophyll with two hydrogens instead of Mg, acts as first acceptor To Plastoquinones PQa and PQb are bound to reaction center and receive electrons from pheophytin PQB is reduced to PQB-2, then takes two protons from stroma, making PQH2, fully reduced PQH2 disassociates from reaction center and transfers electrons to cytochrome b6f |
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Cytochrome b6f (parts!) |
Large, multisubunit protein Two b-type hemes and one c-type hemes Risk iron-sulfur protein Q cycle for proton flow PQH2 is oxidized and one of the two electrons is based down linear process to PS1, other electron enters cyclic cycle |
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Linear Q cycle (pathway) |
First PQH2 is oxidized, so two H+ are released into lumen. One electron is passed to Reiske protein, then to Cyt f, then to plastocyanin Second is passed to Cytb, then heme c, then the PQ is reduced once |
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Cyclic Q cycle (pathway) |
Second PQH2 is oxidized, so two H+ are released into lumen. One electron is passed to reissue, then cut f then plastocyanin Second is passed to cytB, then heme C, then to the once reduce PQ. This fully reduces the PQ. It takes two H+ from the stroma which brings more into the lumen! |
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Mobile Carriers between PS2 and PS1 |
Plastoquinone and plastocyanin |
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Plastocyanin (definition) |
Passes electrons from cytochrome b6f to P700 |
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Photosystem 1 (parts) |
Large multisubunit complex Core antenna consisting of about 100 chlorophyll is integral part of PS1 reaction center Core antenna and P700 are bound to two proteins PsaA and PsaB Core antenna pigments surround electron transfer cofactors |
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Electron acceptors in PS1 (pathway) |
A0, pqhylloquinone Fe-S centers are also electron acceptors Order- A0, A1, FeSx, FeSa, FeSb to Ferredoxin (fd) to ferredoxin NADP reductase (FNR) (do not need to memorize!) |
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How electrons move through photosystem 1 (pathway) |
From PsaA to PsaB to Ferrodoxin to ferredoxin NADP reductase |
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Photophyosphorylation (what is this?) |
Light-dependent ATP synthesis Requires electron flow |
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Chemiosmotic mechanism (definition) |
Difference in ion concentration and electric potential across membrane are sources of energy to be used. Lower concentration in stroma makes energy flow out of cell through ATP synthase |
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ATP synthase (parts, what it does) |
Found only in stroma lamella and at edges of grana stacks Consists of a hydrophobic membrane bound protein (CF0) and a portion that sticks out (CF1) CF1 rotates to make ATP, and one rotation makes three ATP |
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Repair and regulation of photosynthetic machinery (definition, three carotenoids used) |
Too much light can lead to production of toxic O2 species. Carotenoids can take excess energy and protect cell from making toxic O2. Violaxanthin-low Antheraxanthin- intermediate Zeaxanthin- high light PS2 is most affected because it produces 02 specie |
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Photo inhibition (definition, what it does) |
Complex set of molecular processes the inhibit photosynthesis in excess light Reversible in early stages, but later on not Prolonged inhibition requires total replacement of PS2 D1 protein most targed |
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Plastocyanin creation (location) |
Made in cytoplasm by nuclear DNA and imported into chloroplast. |
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Calvin-benson cycle (input, output, location) |
Input- ATP, NADPH, CO2 Output- ADP, NADP+, Carbohydrates Stroma |
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Stages of Calvin-benson cycle (list) |
Carboxylation, reduction and regeneration |
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Ribulose 1, 5-bisphosphate carboxylase/oxygenase (Rubisco) (function, metal ion) |
Slow enzyme that breaks RuBP into 3-phophoglycerate Needs Mg2+ to function |
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Carboxylation step of Calvin-benson cycle (molecules, enzymes, reactions) |
3 RuBP (5 carbon sugar) combine with 3CO2 and 3H2O in Rubisco to make 6 3-phosphoglycerate molecules |
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Reduction step of Calvin-benson cycle
(molecules, enzymes, reactions) |
6 3-PGA are phosphorylated by 6 ATP molecules in 3-phosphoglycerate kinase to make 1,3-bisphosphoglycerate 6 NADPH +6 H+ interact with 1,3-bisphosphoglycerate in NADA-glyceraldehyde 3 phosphate dehydrogenase to make Gylceraldehyde 3-phosphate (G3P) |
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Regeneration step of Calvin-benson cycle (molecules, enzymes, reactions) |
1 G3P is made into starch and sucrose 5 G3P react with 3 ATP to make 3 RuBP over 10 different enzymatic reactions 3 RuBP return to start of cycle |
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Photorespiration (definition, location) |
When Rubisco uses O2 instead of CO2 and forms a toxic byproduct and how it gets rid of the byproduct Takes place in Chloroplast, peroxisome, and mitochondria |
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Calvin-benson cycle reactions net inputs and products |
3CO2 + 5H2O + 6NADPH + 9ATP -----> Glyceraldehyde 3-phosphate + 6(NADP+) + 3(H+) + 9ADP + 8Pi |
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Number of ATP to NADPH needed for fixation of CO2 in calvin-benson reaction |
3:2 |
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Initial mitochondrial steps of photorespiration |
Rubisco uses 2 O2 instead of 2 CO2 and 2 RuBP to make 2 3-Phosphoglycerate and 2 phosphoglycolate (BAD!) 2 Phosphoglycolate and 2 water turn into 2 glycolate |
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Initial peroxisome steps of photorespiration |
2 Glycolate interacts with 2 O2 to make 2 H2O (which is then split) and 2 Glyoxylate 2 Glyoxylate are turned into 2 Glycine |
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Mitochondrial steps of photorespiration |
2 Glycine and NAD+ work with H2O to make CO2, NH3+, NADH and Serine (nitrogen cycling) |
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Final peroxisome steps of photorespiration |
Serine is turned into Hydroxypyruvate Hydroxypyruvate interacts with NADH to make NAD+ and Glycerate |
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Final chloroplast steps of photorespiration |
Glycerinate and ATP make 3-phosphoglycerate and ADP which can return to the Calvin-benson cycle |
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Recovery of Fd (for calvin-benson cycle) (location, enzyme, ingredients) |
In stroma of chloroplast Uses GOGAT Reduced Fd recovers glutamine to glutamate and Fd becomes oxidized in process to return to CB cycle |
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Photorespiration and photosynthesis protection |
Minimizes photo inhibition Prevents over reduction of photosynthetic chain by taking excess reducing equivalents Make H2O2, which is a stress signaling molecule |
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Types of Photosynthesis (list) |
C3, C4, CAM |
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C4 Carbon cycle (why does it exist?) |
Reduce water loss by minimizing photorespiration Add-ons to separate uptake of CO2 and supply to Rubisco to prevent oxygenase from working |
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C4 Leaf anatomy |
Mostly spongy mesophyll Large and well developed bundle sheath Almost no airspaces in mesophyll |
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C4 plants (what type of environment do they do best in?) |
Hot and high illumination because they can make a high concentration of CO2 around bundle sheath cells |
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Label the parts |
A- CO2 B- PEP carboxylase C- Oxaloacetate D- Malate E- CO2 F- Calvin Cycle G- Sugar H- Pyruvate I- ATP J- ADP K- PEP L- Mesophyll Cell M- Bundle-sheath cell N- Vascular tissue |
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C4 Photosynthetic Carbon cycle (pathway) |
PEP Carboxylase catalyzes HCo3- with PEP to make Oxaloacetate Oxaloacetate is converted by NADP-malate dehydrogenase to malate Malate flows to bundle sheath cells and NAD(P)-malic enzyme released CO2 from malate, creating pyruvate CO2 goes to calvin cycle Pyruvate flows back to mesophyll, reacts with pyruvate phosphate dikinase and ATP to regenerate PEP |
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Amount of ATP used in C4 carbon cycle |
Two ATP per mole of fixed CO2 |
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C4 in single cells |
C4 can be in one cell Depends on diffusion gradients, with different types of chloroplasts in different parts of cell |
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CAM Plants (where do they live?) |
Arid environments, good at concentrating CO2 at site of rubisco to save water |
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CAM plants and how they minimize water loss |
thick cuticles, large vacuoles, stomata with small apertures, tight packing of mesophyll cells |
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24-hour CAM cycle with 4 phases (Phase times and enzyme activity) |
Phase I: night Phase II: early morning- increase Rubisco activity Phase III: daytime Phase IV: later afternoon- PEPCase activity increase |
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CAM Dark cycle |
Stomata open for CO2 intake CO2 combines with H2O in cell to make HCO3- PEP Carboxylase takes HCO3- and PEP to male oxaloacetate OAA reduced with NADH by NAD-malate dehydrogenase to make malate and NAD+ Malic acid (low pH in vacuole) stored in vacuole for Light cycle |
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CAM Light cycle |
Stomata closed no CO2 uptake Malic acid made back into malate Malate decarboxylase makes malate release CO2 for Calvin cycle Resulting pyruvate turned into starch |
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Obligate vs Facultative CAM |
Obligate must always use CAM Facultative use C3 when safe but otherwise use CAM. Can change by leaf |
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Sucrose vs Starch (Location in plant, use) |
Sucrose: translocated in phloem and used for energy. Flows from source to sink tissues. Created in cytosol Starch: end product in place it needs to stay i.e. tuber or chloroplast to be used the next day. stored in granules in chloroplast. Long term storage. made in chloroplast |
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Partitioning of Photosynthates (overnight? what happens in sink leaves?) |
Overnight, CO2 assimilation stops, but plant still respires. Uses stored starch to make sugars for energy Low sugar in sink leaves stimulates photosynthesis and mobilizes carbs from storage organs |
