Ch 16 Glycolysis Part 2

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DesLee26
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289857
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Ch 16 Glycolysis Part 2
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2014-11-22 21:04:10
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Final
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  1. ·          In the second stage of glycolysis, a series of steps that harvest some of the energy contained in __ as __.
    ·         The initial reaction in this sequence is the __, a reaction catalyzed by __. 
    • glyceraldehyde 3-phosphate
    • ATP

    • conversion of glyceraldehyde 3-phosphate into 1,3-bisphosphoglycerte (1,3- BPG)
    • glyceraldehyde 3-phosphate dehydrogenase
  2. o   1,3- BPG is an __, which is a mixed __ and a __
    §  Such compounds have a __; one of its phosphoryl groups is transferred to __in the enxt step
    • acyl phosphate
    • anhydride of phosphoric acid and a carboxylic acid
    • high phosphoryl-transfer potential
    • ADP
  3. o   This reaction catalyzed by __ can be viewed as the sum of two processes: the __ and the __
    The first reaction is __, whereas the second is __, with a standard __ of the same magnitude but positive charge
    • glyceraldehyde 3-phosphate dehydrogenase
    • oxidation of the aldehyde to a carboxylic acid by joining of the carboxylic aci and orthophosphate to form the acyl-phosphate product

    • favorable
    • unfavorable
    • free-energy cange
  4. ·         Due to this, the two processes are __so that the favorable __ can be use to drive the formation of the __
    o   The key to coupling is the __that is linked to the enzyme by a __. This intermediate reacts with __to form __
    • coupled 
    • aldehyde oxidation
    • acyl phosphate
    • intermediate 
    • thioester bond
    • orthophospahate 
    • 1,3- BPG
  5. §  The __ is higher in free energy than the __. The __ and __ reactions are coupled by the __, which preserves much of the free energy released in the oxidation reaction
    • thioester intermediate
    • free carboxylic acid is
    • favorable oxidation and unfavorable phosphorylation
    • thioester intermediate
  6. ·         Mechanism of this coupling
    o   The active site of __ includes a reactive __residue, as well as __ and a crucial __
    §  In step 1, the __reacts with the __ on the enzyme to form a __
    Step 2 is the __ that is tightly bound to the enzyme and is adjacent to the cysteine residue
    • glyceraldehye 3-phosphate dehydrogenase
    • cysteine 
    • NAD+
    • histidine
    • aldehyde substrate 
    • sulfydryl group of cysteine 149
    • hemithioacetal
    • transfer of  hydride ion to a molecule of NAD+
  7. ·         This reaction is favored by the __of the __by __
    ·         The products are the __ and __, which has free energy close to that of the reactants
    §  In step 3, __formed from the __ leaves the enzyme and is replaced by a second molecule of __, which is important because the positive charge does what to allow attach by __
    §  In step 4, __ attacks the __to form __and free the __
    • deprotonation 
    • hemithioacetal 
    • histidine 176

    • NADH and a thioester intermediate
    • NADH 
    • aldehyde oxidation
    • NAD+
    • polarizes the thioester intermediate
    • orthophosphate
    • orthophosphate 
    • thioester 
    • 1,3-BPG 
    • cysteine residue
  8. ·         1,3- BPG is energy rich with a greater __ than that of __and can be used to __
    o   __ catalyzes the transfer of the phosphoryl group from the acyl phosphate of 1,3- BPG to ADP
    §  __ and __ are the products
    o   This is __
    • phosphoryl-transfer potential
    • ATP 
    • power synthesis of ATP from ADP
    • Phosphoglycerate kinase
    • ATP and 3- phosphoglycerate
    • substrate-level phosphorylation
  9. ·          The outcomes of the reactions catalyzed by glyceraldehyde 3-phosophate dehydrogenase and phosphoglycerate kinase are as follows:
    o   __, a carboxylic acid
    o   __
    o   __
    • G4P, an aldehyde, is oxidized to 3-phosphoglcerate
    • NAD+ is reduced to NADH
    • ATP is formed from inorganic phosphate and TP
  10. ·         Essentially, the energy released during __ of __ to __ is trapped as __
    o   This energy powers the __ from __ tto ADP to yield ATP
    §  Because two molecules of G3P were formed, two ATP are generated
    • oxidation of glyceraldehyde 3-phosphate to 3-phosphoglycerate
    • 1,3-bisphosphoglycerate
    • transfer of a phosphoryl group
    • 1,3-BGP
  11. ·         In the remaining steps of glycolysis, __ is converted into __, and a second molecule of ATP is formed from ADP
    o   The first reaction is a __. The position of the __ shifts in the conversion of __
    §  A mutase is an enzyme that catalyzes the __, such as a phosphoryl group
    • 3-phosphoglycerate
    • pyruvate
    • rearrangement
    • phosphoryl group
    • 3-phosphoglycerate mutase
    • intramolecular shift of a chemical group
  12. ·         The __ has an interesting mechanism: the __ is not simply moved from one carbon atom to another.
    o   This enzyme requires catalytic amounts of __ to maintain an __ in a __
    §  This phosphoryl group is transferred to __ to re-form __
    • phosphoglycerate mutase reaction
    • phosphoryl group
    • 2,3-BPG
    • active-site histidine residue in a phosphorylated form
    • 3-phosphoglycerate
    • 2,3-bisphosphoglycerate
  13. §  The mutase then functions as a phosphatase, converting __ to __. The mutase retains the phosphoryl group to do what?
    ·         The sum of these reactions yields the mutase reaction: __
    • 2,3-BPG into 2-phosphoglycerate
    • regenerate the modified histidine
    • 3-phosphoglycerateßà2-phosphoglycerate
  14. ·         In the next reaction, the dehydration of __ introduces a __, creating an __. __catalyzes this formation fo the __
    o   This dehydration elevates the __ since the enol phosphate has a high __, whereas the phosphate ester of an ordinary alcohol has a low one. The reason for this high potential is because the __ traps the molecule in its __
    • 2-phosphoglycerate
    • double bond
    • enol
    • Enolase 
    • enol phosphate phosphoenolpyruvate (PEP)
    • transfer potential of the phosphoryl group
    • phosphoryl transfer potential
    • phosphoryl group
    • unstable enol form.
  15. §  Only after donating the phosphoryl group to ATP does it undergo __
    ·         The __ of __arises primarily from the large driving force of the subsequent __
    o   So, pyruvate is formed, and ATP is generated concomitantly
    §  This irreversible transfer is catalyzed by __
    • conversion to a more stable ketone—pyruvate
    • high phosphoryl-transfer potential
    • phosphoenolpyruvate 
    • enol-ketone conversion
    • pyruvate kinase
  16. ·         The formation of pyruvate from__ is an __; __ takes electrons from __ in the conversion of __ into __.
    o   Compared with __, C3 is more __in pyruvate, whereas C2 is more __
    §  __ powers the synthesis of a compound with __, which allows the __
    • 2-phosphoglycerate
    • internal oxidation-reduction reaction
    • carbon 3
    • carbon 2
    • 2-phosphoglycerate into pyruvate
    • 2-phosophoglycerate
    • reduced 
    • oxidized
    • Carbon oxidation
    • high phosphorly-transfer potential
    • synthesis of ATP
  17. ·         The net reaction of glucoseà pyruvate: __


    o   __molecules of ATP are generated in the conversion with an energy release of -96 kJ mol-1

    ·         The conversion of glucose into two molecules of pyruvate results in the net gain of __
    o   __ leads to the reduction of NAD+ to NADH; and, __ must be regenerated for __to proceed. The final process in the pathway does what?
    Glucose + 2 Pi + 2 ADP + 2 NAD+ à 2 pyruvate + 2 ATP + 2 NADH + 2 H+ + 2 H2O

    • Two 
    • 2 ATP
    • Glyceraldehyde 3-phosphate dehydrogenase
    • NAD+
    • glycolysis 
    • regenerates NAD+

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