AGRY 515 Exam II

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MRK
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289534
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AGRY 515 Exam II
Updated:
2014-11-24 15:26:59
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elements functoin
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Cards for exam II
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  1. Ca
    • Membrane CEC and messaging role
    • Immobile
    • In corn leaf edges roll like drought
  2. Fe
    • Oxidation-reduction rxn: Ps, Rd, Nitrate reductase etc.
    • Immoble
    • Morphological ∆ from def: stategy 1 (dicots)  protieod roots and more transfer cells in rhizoderm
    • Physiological ∆ from def: strategy 2 (grasses) enhance synthesis of PS and enhanced release of PS
  3. Mg
    • Central atom of chlorohyll
    • Mobile
    • Intervail chlorosis
  4. Mn
    • Important in PSII
    • Immobile
    • decrease Ps and growth
    • gray spots in small grains
  5. Zn
    • In enyzmes: alcohol dehydrogenase
    • Immoble
    • intervail cholorsis, streaking and weathering
  6. P
    • Helps trigger enzymatic reactions as energy and has a structural role in lipid bi-layer
    • moble
    • Purple corn
  7. K
    • Stomata regulation
    • moble
    • marginal necrosis
  8. S
    • Used for charge balance in the cell and needed for nitrogenaous enzyme
    • Moble
    • Kind a looks like N, yellowing leaves
  9. N
    • Amino acids, protiens
    • moible
    • inverted V in corn ears
  10. Which function is generally non-subsitutaible
    metabolic function
  11. Special deficiency of K
    • build up of smaller building blocks for enzymes
    • it helps assemble them
  12. Structure of ATP
  13. Special P deficency
    • Turn dark-blue
    • cell walls can't extend so concentrated chlorophyll
  14. Special S deficency
    increased level of aa because protien systhesis is inhibited
  15. Which elements are important osoticants
    K, Na, Ca & Mg
  16. Which pool is more highly buffered
    metabolic/osmotic?
    metabolic?
  17. What form of N is stored in the plant
    NO3-
  18. Which form of N is prefered
    • NH4+
    • doesn't need to be reduced
  19. What N sources result in the highest growth rate
    • NH4+ and NO3-
    • balcance pH of the rhizophere
  20. What are the two compoents of nitrogen reduction and where do they occur
    • Nitrate reductace (NO3- -> NO2-)
    • In the cytoplasm
    • Nitrite reducance (NO2- -> NH4+)
    • In chloroplast
  21. Which tissues have the most Nitrate reduciton activity
    • leaves
    • need the light reaction to get rid of NO2-
  22. What factors affect NO3- conentration of transpiring plant?
    • uptake
    • rate of transpiration
  23. What controls location of root or shoot NO3- reduction
    • generally happens in the roots b/c it is low energy and if concentration in soil is low
    • if concentration in soil is high then it happens more in the shoot
  24. How is NH4+/NH3 detoxified in the plant?
    • It is assimilated by GS-GOGAT to make amino acids
    • GS: Glutamine sythetase- NH4+ + glutamate to get glutamine
    • GOGAT: Glutamate sythase- glutamate + 2-oxoglutarate to get 2 glutamates
  25. Major types of microbial strategies for N2 fixing how much N fixed (kg N /ha/ year)
    • Symbiotic: Rhizobium, sucrose from host, nodules (50-400)
    • Associative: Azotobacter, energy from root exudates (10-200)
    • Free-living: Azotobacter, eat plant residue (1-2) or autotrophs (10-80)
  26. Infection process for symbolic N fixation
    • 1. Plant root give off elicitors of Nod gene expression
    • 2. Bacteria releases Nod factor - cause inflection thread to form // root hair curve
    • 3. Infection thread grows into root
    • 4. thread releases bateria cells into cortex
    • 5. forms nodules
  27. What two parts of BNF need carbohydrates
    • Nitogenase enzyme needs 16 ATPS
    • Sucrose for the electron transport chain
  28. Where is O2 needed and not good in BNF
    • Cytochrome oxidase uses O2 to make ATP
    • but need to keep O2 away from Nitrogenase complex.
  29. Which elements are essential for the nitrogenase enzyme
    Mo and Fe
  30. What factors control BNF potential
    • photosynthsis rate
    • N supply in the soil - NO3 depresses nodulation
    • Crop demand for N (feedback/build up)
    • adequte P and Fe needed for nodulation
    • water stress
    • different temperature optimums
    • basic pH (Ca) for infection thread
  31. How does K effect stomatal movement and why?
    • causes them to move
    • K is pumped into the cytoplasm - to open
    • water follows to reduce concentration
    • to close is fast, K to vacole w/o ∆ pH (pump out H+ and in Cl- ??
  32. 3 reasons why non-legumes grow best on a combination of NO3 and NH4 as N source
    • - charge balance
    • - Too much energy to reduce NO3 if that only taken up
    • - both are used in chlroplast to make products for amino acids (Nitrogen assimulation)
    • - keeps Mo supply need low
  33. 3 micronutrients that help break down free radicals
    • Cu Zn, Fe for SOD- superoxide dismutases
    • they can accept the extra e- on O2- so that it does not attack lipids, protiens etc.
  34. ID 3 elements that serve as redox reagents
    for one explain a specific purpose
    • Fe, Cu, Mo
    • Cu- is in plastocyanin for e- transport in PSI
  35. Why do Zinc deficent plants have high concentrations of Cl and B in their leaves
    • If low Zn -> low Zn SOD -> membranes damaged -> rapid uptake of Cl and B
    • High P content can cause phytic acid build up which ties up Zn
  36. Four groups of functions
    • 1. Structural componets of biological compound and intermediates of metabolism
    • 2. Enzyme activators
    • 3. Redox reagents
    • 4. Uncertain function
  37. Why is plant S status important for preventing Cu and Zn deficiency
    S helps create photochelatins which bind heavy metal like Cu and Zn
  38. two examples of how SO4 assimilartion differes form NO3
    • SO4 doesn't have to be reduced- NO3 does
    • Once NO3 is reduced it stays that way, where SO4 is useful because it can go both ways
  39. which takes more K - Photosynthesis or RU-BP?
    • Ru-bp
    • but both need
  40. What can substitute for K osmotic role
    Ca
  41. Too much K can cause stomtal difficulties
    true because need concentration gradent
  42. Photosynthesis v. Leaf water potental under very low, suffecent and high K
  43. Ca distribution in cell: 2 high and 1 low location
    • High: Vacuole and Endoplasmic reticulum
    • Low: in cytoplasm
  44. Photosiderophore
    • non-protien amino acid
    • made in response to lack of Fe in grasses
    • pumped out, picks up Fe 3+ and brings it in together
  45. Transfer cells
    • Used by dicots to increase uptake of Fe2+
    • More made in the rhizoderm-> outer most layer of corticle cells in the root
  46. What toxicity problems are enhanced by acid soils
    • Fe, reduced by availble H+
    • Zn
    • Mn
  47. What defecincy problems are enhanced in acid soils
    • Zn
    • Mo
  48. Cu: role, mobile deficiency
    • main functions redox capablities
    • immoble
    • low carbohydrated abailibty because reduced PSI and PSII, sterility not enough carbohydrate
  49. Interactions of Mo and NH4 NO3
    • Mo requirement is low if N requirement is low
    • If higher in NH4 increase Mo requirement for legumes opposite for non-legumes
    • If higher in NO3 don't need Mo for legumes opposite for non-legumes because don't need nitrate reductase
  50. Probable roles of B in the plant
    • don't really know, no radio tracers and difficult chemistry
    • NOT enzyme activator,
    • cell wall synthesis and maintenance
    • pollen tube formation
    • order of vascular tissue
  51. B uptake active or passive?
    • Active b/c vary much
    • folair application is good b/c moves with the transpiration stream
  52. Ni info
    needed in urase enzymne to work and break down urea
  53. Cl
    good ion for isomotic potential balance
  54. Why? P application reduced symptoms of N deficiency in a legume?
    • Because P is needed in high rates for nodule development and high rates of N2 fixation
    • 16 ATPs for Nitroganse enzymne complex
  55. S application reduced symptoms of Cu toxicity?

    Why?
    Cu will complex with sulfhyral groups and not be avalible for uptake
  56. Switching from NH4+ to NO3- as the N source increases the proportion of N in protein form
    (i.e. increases protein synthesis) in a non-legume and enhances the starch
    content of a tuber. -Why?
    • reduction happens in the shoots which is more effecient
    • so more starch
  57. A sewage sludge application induces Ca, Fe and / or Mg symptoms on a variety of different sites?
    all 2+ get tied up in OM
  58. Plants grown on a field receiving optimal macronutrient supplies have smallish leaves with very high P, Cl, and B concentrations.
    Why?
    • Zn deficiency
    • High P = ties up Zn in phytic acid
    • High Cl and B uptake because membranes are damaged from lack of Zn SOD to take care of super oxide
  59. Storage form of P
    • phytin - 6 phosphate groups + C and is expensive so not luxury consumed
    • vacoule
  60. What caueses protiod root production
    N, Fe, and P deficiency
  61. How is Sulfate similar/ different to Nitrate assimilation
    • Both leach in the soil
    • both must be reduced
    • N can't go back
  62. What is phytochelatin
    polipeptieds high in cystine important in binding heavy metals
  63. S is stored in Sulfate so it is the best way to assess S status
    true
  64. Ca has micro and macro functions
    • micro- signaling/ secondary measanger in the cytoplasm and enzyme activiator of sucrose
    • Macro- essential for membrane permiablity
    • Mg is also distributed that way
  65. What is Ca modulin?
    • an enzyme that is activitated by Ca
    • allows calmodulin expression
  66. Why are root uptake rates down with Mg defeciency
    • because PS is negatively impacted root growth is down
    • Mg can can replace K in osmoitc role
  67. Discribe the function of Ca where it is in high concentration
    • Middle lamella: for stabilty and struture, can be subsitiuted by Mg or Al not very well
    • Exterior of plasma membrane: bridges phosphate and carboxylate groups, can be subusituted with Na causes salinity problems
    • Vacuole: osmo-regulation, K well
  68. Why is concentration of Ca low in cytoplasm?
    • binds with Pi and precipates
    • competition with Mg
    • needs to be low for messaging and enzyme activator role
  69. How does Ca supply affect disease susceptibilty
    • cell walls deteriorate = pathogens enter
    • K is similar because key role in water relations

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