BI220 - Glycolysis and Pyruvate Oxidation

location

cytosol

function

• split 6-C glucose into sugars

  • C rearranged into 3-C pyruvate

phases

• energy investment

• energy payoff

is O2 required

no

energy investment phase

use ATP to rearrange glucose and to promote its eventual breakdown

PFK

allosterically regulated by ATP and its products to shut off pathway when sufficient ATP

how many G3P is generated during investment phase

2

energy payoff phase

• 2 ATP + 2 ATP generated as glucose is broken down

• more potential E captured by reduction of NAD+ to NADH

  • 9 different products

  • 10 different enzymes

steps of energy payoff phase (6)

• transfer of 2 e- from G3P to NAD+

  • one Pi added

• substrate level phosphorylation

  • repay debt of investment phase

• rearrangement of molecules

  • P group

• enolase catalyzes loss of water

• creation of double bond creates potential energy

• substrate level phosphorylation now have net gain of ATP

enolase

catalyze loss of H2O

glycolysis net reaction

1 glucose (6C) mol → 2 pyruvate (3C) mol

ATP consumption

2 ATPS molecules during investment

NADH creation

2 NADH + H+

• one for each 3C sugar

ATP creation

4

net ATP production

2

draw box representing glycolysis

after glycolysis if O2 present

• aerobic respiration

  • pyruvate converted and moved to mitochondria

after glycolysis is O2 absent

• anerobic respiration/fermentation

  • pyruvate stays in cytosol

pyruvate oxidation steps (3)

• carboxyl group snipped from pyruvate

  • release CO2

• 2C molecule oxidized and e- passed to NAD+ to create NADH

• CoA bond to acetate to form Acetyl CoA

  • very high potential energy