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29 Cards in this Set
- Front
- Back
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What is an autotroph?
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An organism that can produce complex organic molecules from inorganic molecules, using light (photosynthesis) or chemical energy (chemosynthesis)
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What is a Heterotroph?
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Gains energy by ingesting and digesting complex organic molecules, releasing the chemical potential energy sorted in them.
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What is the relationship between respiration and photosynthesis?
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Respiration in plants and animals depends on photosynthesis as photosynthesis releases oxygen and carbon compounds (e.g Glucose) which form the basis of ATP
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What is the equation for photosynthesis? |
6CO2 + 6H2O ---> C6H12O6 +6O2 |
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Where does Photosynthesis take place?
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Chloroplasts
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How does the structure of the Chloroplast enable them to carry out their function?
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-outer membrane: permeable to many small ions -inner membrane: less permeable; has embedded transport proteins -stroma: fluid-filled matrix; reactions of the light-independent stage of photosynthesis occur (starch grains, oil droplets, DNA, and ribosomes also here to make membranes and proteins) -grana: large surface area for light absorption and ATP synthesis |
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What is a photosynthetic pigment?
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Pigment that absorbs certain wavelengths of light and reflect others
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What is the importance of photosynthetic pigments in photosynthesis?
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-absorb certain wave lengths of light -arranged in photosystems where accessory pigments surround the reaction centre where the primary pigment Chlorophyll A is found. -photons from light hit pigments and excite electrons causing energy transfer between pigments until it reaches the reaction centre where it excites and donates a pair of electrons |
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Where does the light dependant stage of photosynthesis occur?
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Thykaloid membranes
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Where does the light independent stage of photosynthesis occur?
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Stroma
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What are the products of the light dependant stage of photosynthesis?
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- ATP and reduced NADP are produced |
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What is photolysis?
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The splitting of molecules through absorption of light
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What are the photosystems involved in the light-dependant stage of photosynthesis and where are they found?
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-Photosystem 1 and 2 (PSI and PSII)# -PSI = intergranal lamellae -PSII = granal lamellae |
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Where does photolysis happen and what happens?
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-Photosystem 2 (PSII) - enzyme splits water into H+ ions (protons), electrons and O2 in the presence of light - 2H2O ---> 4H+ + 4e- + O2 |
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What is the role of water in the light dependant stage of photosynthesis? (Outline what happens)
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-Water is a source of protons (H+ ions) which are used in chemiosmosis to produce ATP -Protons are accepted by NADP which then becomes reduced NADP -Electrons from water replace those lost by oxidised chlorophyll -Byproduct of oxygen is produced |
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What is photophosphorylation?
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The making of ATP using light energy
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What happens in photophosphorylation?
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- photon hits chlorophyll; excites two electrons; electrons captured by electron acceptors and passed along electron carriers (electron transport chain- ETC) - electrons lose energy as they go down the ETC; energy is used to pump protons into thylakoid space to form a proton gradient -protons flow down gradient through channels associated with ATP Synthase; causes ADP and Pi to make ATP -Kinetic energy from proton flow is converted into chemical energy in ATP for light independent. |
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What are the two types of photophosphorylation?
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Cyclic and Non-Cyclic
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What happens in cyclic photophosphorylation?
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-uses only PSI -excited electrons pass to an electron acceptor and back to the chlorophyll molecule -no photolysis of water -no generation of reduced NADP -small amounts of ATP produced |
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What happens in non-cyclic photophosphorylation?
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-uses both PSI and PSII -photolysis of water occurs -reduced NADP formed -electron pair leaving PSII passes along electron carriers to ATP synthesis -electron pair leaving PSI reduces NADP -pair from PSII replace pair lost PSI -electrons from photolysed water replace those lost by the oxidised chlorophyll in PSII |
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What is the light independent stage also know as?
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The Calvin Cycle |
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What happens in the Calvin Cycle?
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1) CO2 diffuses into leaf through stomata through air spaces in spongy mesophyll and reaches the palisade mesophyll layer where it diffuses into the stroma 2) CO2 combines with CO2 acceptor RuBP (Catalysed by rubisco) and produces GP (carboxylation) 3) GP reduced and phosphorylated to TP; ATP and reduced NADP from light dependent stage are used here (reduction) |
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What can TP and GP make?
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Carbohydrates, lipids and amino acids
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What does CO2 do in the light-independent stage?
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Provides a source of carbon to produce large organic molecules
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What is a limiting factor?
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The factor in the lease favourable amount
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What is the importance of carbon dioxide concentration in photosynthesis?
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needed for the Calvin Cycle
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What is the importance of light intensity in photosynthesis?
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-opens stomata -allows CO2 to enter leaves -excites electrons -used in photolysis of water and photophosphorylation |
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What is the importance of temperature in photosynthesis?
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-effects enzyme action (e.g rubisco in Calvin Cycle) - raised temp means O2 can compete with CO2 for the active site on rubisco and causes more water loss which will close the stomata and prevent CO2 entering |
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How would you measure the rate of photosynthesis?
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-use a photosynthometer or Audrus microburette
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