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38 Cards in this Set
- Front
- Back
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what are the stages of the calvin cycle? |
. carbon dioxide from the atmosphere diffuses into the leaf through stomata and dissolves in water around the walls of the mesophyll cells . then diffuses through the plasma membrane, cytoplasm and chloroplast membranes and into the stroma . carbon dioxide combines with ribulose biphosphate using an enzyme (RuBP) . this produces two molecules of glycerate 3 phosphate (GP) . ATP and reduced NADP are used to reduce the (GP) to triose phosphate (TP) . NADP is reformed and goes back to the light independent reaction . some triose phosphate molecules are converted to be used as useful organic substances such as glucose . most triose phosphate molecules are used to regenerate ribulose biphosphate using ATP from the light independent reaction |
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how is the plant leaf adapted to carry out photosynthesis? |
. large surface area to absorb sunlight . the arrangement of leaves on the plant minimises overlapping so all leaves get a maximum amount of sunlight . thin . transparent cuticle . numerous stomata . network of xylem |
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what are the main stages of photosynthesis? |
. 6CO2 + 6H2O = C6H12O6 + 6O2 . capturing of light energy . the light dependant reaction . the light independent reaction |
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what is the structure and role of chloroplasts in photosynthesis? |
. grana/thylakoids is where the light dependant reaction occurs . The stroma is the fluid filled matrix where the light independent stage of photosynthesis takes place - has lots on enzymes, DNA and ribosomes, starch grains and lipids |
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what is the purpose of the light dependant reaction? |
. requires water, requires light . to add an organic phosphate molecule to ADP thereby making ATP . Split water to H+ ions and OH- ions via photolysis . makes NADP |
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what are oxidation and reduction? |
. when a substance combines with oxygen the reaction is called oxidisation - looses electrons . when a substance loses oxygen the reaction that occurs is called reduction - gains electrons |
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how is ATP made during the light dependant reaction? |
. chlorophyl molecule absorbs energy, boots the energy in a pair of electrons that are said to get 'excited' . leave the chlorophyl molecule altogether . taken p by a electron carrier . chlorophyl molecule is oxidised . electron carrier is reduced . passed along electron carrier chain in a series of oxidisation reduction reactions . located in the thylakoids . the energy lost is used to combine ADP to a phosphate |
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what is the equation for the photolysis of water? |
H2O = 4H+ + 4e- + 4H+ |
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what is the ole of photolysis in the light dependant reaction? |
. loss of electrons need to be replaced . this is done by the splitting of water by sunlight energy via the reaction called photolysis . hydrogen ions (protons) are take up by an electron carrier called NADP . on taking these up the carrier becomes reduced . the reduced NADP then enters the light independent reaction . water diffuses out as a by product of respiration |
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how are the chloroplast adapted to carry out the light - dependant reaction? |
. thylakoids of the chloroplasts . provide a large surface area for attachment of chlorophyll, electron carriers and enzymes . network of proteins in the grand hold the chlorophyll in a manner that allows the maximum absorption of light . granal membranes have enzymes attached to them, that help manufacture ATP . Chloroplast contain both DNA and ribosomes for protein synthesis |
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what is a coenzyme |
molecule that is required for the function of an enzyme |
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what is the site of the light independent reaction? |
. fluid of the stroma contains all enzymes needed to carry out the light independent reaction . the stroma flood surrounds the grana so products can really diffuse into the stroma . contains both DNA and ribosomes fro protein synthesis |
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what is meant by the concept of limiting factors? |
. a limiting factor is the factor that limits the rate at which the process can take place . changing other factors of this process with not alter the rate of the process
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what are the limiting factors of photosynthesis? |
. light intensity - high . Carbon Dioxide concentration - 0.4% . water availability . temperature - 25oc . wavelength - blue light |
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why are plants green? |
green wavelength is reflected |
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what is a saturation point? |
. where a factor is no longer limiting the reaction - something else has to become the limiting factor |
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what is respiration? |
. respiration is the process that allows cells to produce ATP from glucose . it can be done aerobically or anaerobically |
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what is a coenzyme? |
a molecule that aids the function of an enzyme by transferring a chemical group from one molecule to another |
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what coenzymes are used in respiration? |
. NAD and FAD - transfer hydrogen from one molecule to another, they can reduce or oxidise a molecule . Coenzyme A - transfers acetate between molecules |
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what are the four stages of aerobic respiration? |
. Glycolysis . The link reaction . the Krebs cycle . oxidative phosphorylation - all of above used to produce ATP in this stage |
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what happens during Glycolysis? |
1) phosphorylation . glucose is phosphorylated by adding 2 pi from 2 molecules of ATP . creating 2 TP and 2ADP 2) Oxidation . TP is oxidised forming 2 molecules of pyruvate . NAD collects hydrogen ions forming 2 reduced NAD . 4 ATP are produced but two were used up in stage 1 so there is a net overall gain of 2 ATP |
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what are the products from glycolysis and where do they go? |
. 2 reduced NAD to oxidative phosphorylation . 2 pyruvate to the link reaction . 2 ATP net gain used for energy |
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what happens during the link reaction? |
. converts pyruvate to acetyl coenzyme A . pyruvate is decarboxylated - one carbon atom is removed in the bi product of carbon dioxide . NAD is reduced from pyruvate, changing pyruvate into acetate . acetate is combined with coenzyme A . no ATP is produced in this reaction |
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how many times does the link reaction occur per glucose molecule? |
. two pyruvate molecules are made for every glucose . the link reaction and Krebs cycle happen twice for every glucose molecule |
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what are the products from two link reactions? |
. 2 acetyl coenzyme A to the Krebs cycle . 2 carbon dioxide released as a waste product . 2 reduced NAD to oxidative phosphorylation |
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what happens during the Krebs cycle? - formation of citrate? |
1) Formation of citrate . Acetyl CoA from the link reaction combines with oxaloacetate to form citrate . CoA goes back to the link reaction to be used again |
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what happens during the Krebs cycle? - Formation f a 5-Carbon compound |
2) Formation of a 5-Carbon compound . 6C citrate i converted to 5C molecule . decarboxylation occurs and Carbon dioxide is removed . Dehydrogenation also occurs . hydrogen is used to produce reduced NAD from NAD |
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what happens during the Krebs cycle? - Regeneration of oxaloacetate
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3) Regeneration of oxaloacetate
. 5C molecule is converted to a 4C molecule . Decarboxylation and dehydrogenation occur, producing one molecule of reduced FAD and two of reduced NAD . ATP is produced by the direct transfer of a phosphate group from ADP . this is called substrate-level phosphorylation |
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what are the products of the Krebs cycle? |
. 1 CoA goes back to the link reaction to be reused . oxaloacetate is regenerated for use in the next Krebs cycle . 2 Carbon Dioxide released as a waste product . 1 ATP used for energy . 3 Reduced NAD to oxidative phosphorylation . 1 Reduced FAD to oxidative phosphorylation |
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how else may reduced FAD and reduced NAD be written? |
FADH2 and NADH |
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what is decarboxylation? |
is the removal of carbon dioxide from a molecule |
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what is the process of oxidative phosphorylation for? |
. where energy carried by electrons from reduced coenzymes (NAD and FAD) is used to made ATP |
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what are the first four steps of oxidative phosphorylation? |
. hydrogen atoms are released from NADH and FADH2 as they're oxidised to NAD and FAD .hydrogen atoms split to e- and H+ . electrons move along ETC loosing energy at each carrier . energy is used to pump protons from the mitochondrial matrix into the inter membrane space |
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what are the middle two steps of oxidative phosphorylation? |
. Concentration of protons is now higher in the inter membrane space than in the mitochondrial matrix . this forms an electro chemical gradient which protons move down back into the matrix via ATP synthase |
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what are the last 3 steps of oxidative phosphorylation? |
. the movement drives synthesis of ATP from ADP and pi and (the movement of H+ ion across a membrane which generates ATP is called chemiosmosis) . in the mitochondrial matrix, at the end of the chain, the protons, electrons and oxygen from the blood combine to form water. . Oxygen is said to be the final electron acceptor . |
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where do all the ATP molecules come from for one molecules of glucose in aerobic respiration? |
glycolysis = 2 ATP glycolysis = 2 reduced NAD = 2 x 2.5 link reaction x2 = 2 reduced NAD = 2 x 2.5 krebs cycle x2 = 2 ATP krebs cycle x2 = 6 reduced NAD = 6 x 2.5 kerbs cycle x2 = 2 reduced FAD = 2 x 1.5 Total = 32 ATP |
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what happens in aerobic respiration to pyruvate? |
Alcoholic fermentation . happens in plants and yeast . pyruvate - ethanol by the release of CO2 . - (NADH - NAD) - ethanol Lactate fermentation . pyruvate - (NADH- NAD) - lactic acid |
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what is ATP? |
. ATP is the immediate source of energy in a cell. . It is used to carry out biological processes |
