biochem- lecture 1_glycolysis phase 1 (slides 1-38)

what are the two goals of glycolysis
Click the card to flip 👆
1 / 30
Terms in this set (30)
What funnels both dihydroxyacetone phosphate and glyceraldehyde 3 phosphate into one pathway?that they are interconvertableWhat is a reverse aldol condensation?when a beta-hydroxy carbonyl compound is split into an aldehyde or ketone plus a carbonyl compoundwhich enzymes in glycolysis phase 1 facilitate phosphorylationhexokinase and phosphofructo kinasewhat enzyme in glycolysis facilitates the reverse aldol condensationaldolasewhich steps are reversable in phase 1 of glycolysis and whythe reversable steps in glycolysis are: 1. glu6P to fru6P 2. fru1,6-bisP to Gly-3-P + dihydroxyacetone-Penergetics of glycolysis rxn 11. glu -> glu-6-P ---- irreversible because atp hydrolyis is -30.5 and phosphorylation is + but less than +30.5 so it is exergonic when coupled with atp hydrolysisenergetics of glycolysis rxn 2 how is it pulled forward?glu-6-P -> fru-6-P slightly endergonic but close to zero, therefore it is reversable -product concentration kept low by pairing with favorable next step to drive forwardenergetics of glycolysis rxn 3 what is the enzymefru-6-P -> fru-1,6-bisP endergoinc step made exergonic by coupling with ATP hydrolysis irreversable enzyme: phosphorfructokinase-1 (PFK-1)what is the first regulated step in glycolysisfru-6-p -> fru-1,6-bisP regulated because it is irreversable and is a committing step and it uses PFK-1 which is a allosterically inhibited enzymewhy would a cell want to inhibit ATP productionif levels of ATP are considerably high, it makes sense to slow down production so there is not a large excess of energy being stored.what inhibits PFK-1 in early steps of glycolysishigh ATP levels in the step where fru-6-P is made into fru-1,6,bisPADP levels are high in the cell. What can adenylate kinase do to squeee a bit more ATP out for energy?2ADP -> ATP + AMPif ATP,ADP, and AMP ratio runs down to only amp, more ATP needs to be made. How can AMP trigger more ATP productionamp is an allosteric activator of pfk-1 in glycolysis so pfk-1 senses amp and recognizes that glycolysis needs to pick up the does pfk-1 make more ATP by being activated by amp levelsit responds by sending more sugar units into glycolysiscan an enzyme be inhibited by an allosteric and a competitive inhibitor at the same timeyesenergetics of glycolysis rxn 4 of glycolysis how is it pulled froward? (coupling, free energy, and concentration)fru-1,6-bisP to dihydroxyacetone phosphate + glyceraldehyde 3 phosphate very unfavorable reaction, very endergonic, very reversable pulled forward by coupling with next rxn which consumes the products and is very exergonic and by the overall free energy of glycolysis produced. Additionally, glyceradlehyde 3 P concentration is kept low to further pull frowardwhat is a common intermediate when converting an aldose to ketoseenediolif the aldol cleavage of fru-1,6-bisP is very unfavorable, describe why keeping glyceraldehyde 3 phosphate concentrations low helps it happenthe free energy requirement is very high but is we keep product concentrations low then less energy is required overall vs having product concentration very high which would require a lot of energywhat is the enzyme that catalyzes the conversion of dihydroxyacetone phosphate to glyceraldehyde 3-P is this reaction reversible, what is the energy?triose phosphate isomerase the rxn is reversable and is endergonic but fairly close to zerowhat two reactions in glycolysis are conversions between ketose and aldoseglu-6-p to fru-6-p (aldose->ketose) and dihydroxyacetone phosphate to glyceraldehyde three phosphate (ketose->aldose)