Lecture 302: glycolysis Flashcards
glycolysis
- generates energy and intermediates for other processes and pathways
- nearly universal in all organisms
glycolysis generates energy for
- brain [glucose primary]
- skeletal muscles
- RBS’s [can use glucose as energy]
excess dietary glucose converted to ____ in glycolysis
fat
glycolysis is a _____ pathway where glucose is oxidized to ____
- catabolic pathway
- pyruvate
glycolysis invests ____ and generates ____
- 2 ATP
- 4 ATP and 2 NADH
glycolysis step 1
- hexokinase = puts phosphate group on glucose to make G6P
- FIRST INVESTMENT = requires ATP
- traps glucose in the cell
- irreversible and regulated step
hexokinase 1, 2 and 3 have (different/ similar) affinities for glucose and (high/ low) Km
- similar
- low Km
hexokinase 4 has (high/ low) affinity for glucose and a (high/ low) Km; used in the liver during ____
- low affinity
- high Km
- gluconeogenesis
glycolysis step 2: function of phosphoglucoseisomerase
- rearrangement of atoms to make fructose-6-phosphate
- sets up the molecule for subsequent reactions:
- C1 -OH group can be phosphorylated in step 3
- symmetrical cleavage in step 4
glycolysis step 3: function of phospofructokinase-1
- 2ND INVESTMENT = requires ATP and Mg+
- irreversible
- PFK-1 transfers a phosphate group from ATP to F6P to make F1,6BP
- primary site of regulation in glycolysis
primary site of regulation for glycolysis
phosphofructokinase-1
glycolysis step 4: aldolase
- reversible [highly exergonic]
- symmetrical cleavage of F1,6BP into DHAP and GAP
glycolysis step 5: triose phosphate isomerase
- readily reversible
- isomerizes DHAP to G3P
glycolysis step 6: glyceraldehyde-3-phosphate-dehydrogenase
- generates NADH
- costs one phosphate molecule but NOT from ATP
- reversible
- converts GAP to 1,3BPG
glycolysis step 7: phosphoglycerate kinase
- generates ATP
- reversible
- removes Pi group from C1
