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Photosynthesis

lele_star Biology Englisch 37 Karten

Karten in diesem Stapel (37)

  1. 1where does the light dependent stage of photosynthesis take place?The thylakoid membranes
  2. 2what is photolysis?The splitting of water into protons, electrons and oxygen, takes place in photosystem 2 (non cyclic photophosphorylation)
  3. 3what happens to the water once it has been photolysed?-protons are used in chemiosmosis, are then accepted by the coenzyme NAD to form NADH used in the LIS
    -electrons replace those lost by the oxidised chlorophyll in photosystem 2
  4. 4what happens after a photon of light hits a photosystem?The energy of the photon is transferred to tow excited electrons which are captured by electrons acceptors and are passed down a series of electron carriers (proteins containing iron) in the thylakoid membranes
  5. 5what happens when the electrons are passed down the electron carriers?Energy is released which allows protons to be pumped across the membranes into the thylakoid space where they accumulate. Forming a proton gradient. Protons flow down the gradients through channels associated with ATP synthase
  6. 6what is chemiosmosis?The flow of hydrogen ions through ATP synthase enzymes. Force drives the rotation part of the enzyme causing ATP to be produced
  7. 7What are the products of the light dependent stage?-Reduced NADP
    -ATP (by photophosphorylation)
  8. 8what is cyclic photophosphorylation?uses only photosystem 1, excited electrons pass to an electron acceptor and back to the chlorophyll molecule they were lose. No photolysis of water, no NADPH but small amounts of ATP
  9. 9What can the ATP made from cyclic phosphorylation be used for?-used in the light independent reaction
    -may be used in guard cells to bring in potassium ions, lowering the water potential and causing water to follow by osmosis. Guard cells swell and open the stomata
  10. 10What is non cyclic phosphorylation?Uses both photosystems, like strikes both causing photolysis of water and electron transfer. Produces NADPH and ATP which are taken to the stroma
  11. 11where does the light independent stage/calvin cycle take place?The stroma
  12. 12What is the enzyme required for the calvin cycle?Rubisco- fixes carbon dioxide to ribulose bisphosphate (RuBP)
  13. 13how does co2 get to the stroma?Diffuses into the leaf through open stomata (underside of the leaf) diffuses through air spaces in the spongy mesophyll unit it reaches the cytoplasm and the chloroplast envelope and into the stroma
  14. 14what happens to GP? (Glycercate 3 phosphate)GP is reduced and phosphorylated to another 3 carbon compound triose phosphate TP. (ATP and reduced NADP from the light dependent reaction are used in this process)
  15. 15How much TP is used to regenerate Ribulose Bisphosphate?5 out of every 6 molecules of TP (3C), this uses ATP from the light dependent reaction to produce 3 molecules of RuBP (5C)
  16. 16What can 1 molecule out of 6 TP be used for?-amino acids, fatty acids, glycerol (f +g=lipids) -pairs can form hexose sugars e.g. glucose which can be isomerised to fructose. Fructose n glucose combine to make sucrose- sugar translocated in phloem sieve tubes. Hexose sugars can be polymerised to cellulose and starch
  17. 17what is the definition of the light independent reaction?The stage of photosynthesis where carbon dioxide is fixed and used to build complex organic molecules
  18. 18Photosynthetic pigmentsAre in the thylakoids membranes arranged in funnel-shaped structures called photo systems, held in place by proteins
  19. 19What are the two types of chlorophyll aP700 =1 p680=2
  20. 20What happens when light hits chlorophyllCauses a pair of electrons associated with the magnesium to become excited
  21. 21What is the primary pigment centreThe centre of the photo system made up of chlorophyll a (700 and 680)
  22. 22Give two examples of accessory pigmentsCarotene (orange)
    Xanthophyll (yellow)
  23. 23What do accessory pigments do?Absorb wavelengths that are not well absorbed by chlorophylls and pass the energy associated with that light to the chlorophyll a at the base of the photo system
  24. 24Define the term heterotrophOrganisms that ingest and digest complex organic molecules releasing the chemical potential energy stored in them
  25. 25What is photosynthesis?The process whereby light energy from the sun is transformed into chemical energy and used to synthesise large organic molecules from inorganic substances
  26. 26Why does respiration in plants and animals depend on the products of photosynthesis?As they use oxygen, a product of photosynthesis for respiration, animals rely on photosynthesis so that light energy can be transformed to chemical potential energy which they can breakdown
  27. 27Where does photosynthesis take place?Takes place in the chloroplasts. It is a two stage process 1. Light dependent 2. Light independent/ Calvin cycle
  28. 28Name the key structures in a chloroplast-an outer membrane and inner membrane which make the envelope -stroma -grana -thylakoids -photosynthetic pigments -accessory pigments
  29. 29Describe the outer membrane of a chloroplastIt is permeable to small ions
  30. 30Describe the inner membraneLess permeable to ions, has transport proteins embedded in it. It is folded into a lamellar which are in stacks. Each stack is called a granum (grana) between the grana are intergranal lamellae
  31. 31Describe the stromaA fluid filled matrix where the light independent stage takes place. Contains necessary enzymes such as ATP synthase, oil droplets, starch grains (store glucose) and DNA and ribosomes
  32. 32Describe the granaStacks of flattened membrane compartments called thylakoids. Stage of the light dependent reaction, contains ATP synthase. Thylakoids can be seen using an electron microscope
  33. 33How does the adaption of the inner membrane help its role?Has transport proteins, can control what enters and exits the membrane
  34. 34How does the adaption of the grana help its role?Provides a large surface area for photosynthetic pigments, electron carriers ATP synthase which are required for the LDR
  35. 35How are photosynthetic pigments arranged?In special structures called photo systems which allow maximum absorption of light energy. Proteins embedded in the grana hold the photo systems in place
  36. 36How does the adaption of the mitochondria and DNA in the chloroplast to help its role?Allows the required proteins to be made for photosynthesis, using genetic instructions in the DNA and the chloroplast ribosomes to assemble proteins
  37. 37Define the term autotrophOrganisms that use light energy or chemical energy and inorganic molecules (Caron dioxide and water) to synthesise complex organic molecules

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Biology Karteikarten am Photosynthesis, erstellt von lele_star am 04/06/2013.
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