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18 Cards in this Set
- Front
- Back
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What important molecules are produced by the pentose phosphate pathway?
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NADPH and 5 carbon sugars (pentose), specifically ribose
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What is the first step in the pentose phosphate pathway?
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glucose 6-phosphate is oxidized by glucose 6-phosphate dehydrogenase to form 6-phosphogluconolactone.
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Which step in the pentose phosphate pathway is regulated?
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The first step.
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How is glucose 6-phosphate dehydrogenase regulated?
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Allosterically inhibited by NADPH.
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Why does the cell require NADPH?
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To reduce ribonucleotides to deoxyribonucleotides for DNA synthesis.
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Why does the cell require ribose 5-phosphate?
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As a precursor of ribonucleotides and deoxyribonucleotides.
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What are the enzymes of the oxidative stage?
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glucose 6-phosphate dehydrogenase, gluconolactonase, and 6-phosphogluconate dehydrogenase.
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What are the enzymes of the nonoxidative stage?
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ribulose 5-phosphate 3-epimerase, ribose 5-phosphate isomerase, transketolase, and transaldolase
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What is the difference between the jobs of transketolase and transaldolase?
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transketolase transfers a 2 carbon aldol moiety and transaldolase transfers a 3 carbon keto moiety.
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What is another name for transaldolase?
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dihydroxyacetonetransferase, because it catalyzes the transfer of a 3 carbon dihydroxyacetone group from a ketose phosphate to an aldose phosphate.
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What is another name for transketolase?
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glycoaldehydetransferase, because it transfers a 2 carbon glycoaldehyde group from a ketose phosphate to an aldose phosphate.
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Which enzyme is dependent on thiamine pyrophosphate (TPP)?
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transketolase
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What is the balanced equation for the pentose phosphate pathway?
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3 glucose 6-phosphate + 6 NADP+ + 3 H2O --> 2 fructose 6-phosphate + glyceraldehyde 3-phosphate + 6 NADPH + 3 CO2 + 6 H+
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What is the balanced equation for the oxidative stage of the pentose phosphate pathway?
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glucose 6-phosphate + 2 NADP+ + H2O --> ribulose 5-phosphate + 2 NADPH + CO2 + 2H+
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What is the substrate of gluconolactonase?
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6-phosphogluconolactone
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What is the substrate of 6-phosphogluconate dehydrogenase?
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6-phosphogluconate
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What product is formed by ribulose 5-phosphate 3-epimerase and ribulose 5-phosphate?
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2,3-enediol intermediate which converts to xylulose 5-phosphate
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What product is formed by ribulose 5-phosphate isomerase and ribulose 5-phosphate?
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1,2-enediol intermediate which converts to ribose 5-phosphate.
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