KREBS CYCLE

• Occurs in the mitochondrial matrix; cytosol of prokaryotes
• Begins when 2-carbon Acetyl CoA combines with 4-carbon OAA (oxaloacetate) to form citrate                                   
  • Citrate functions as inhibitor of glycolysis
• Result:
  • 2 CO2 molecules produced
  • 6 NADH created
  • 2 FADH2 created: makes less ATP bcuz transfers electrons at lower energy level
• Electrons are transferred to coenzymes NADH and FADH2 that will donate electrons to be oxidized and then reused
• 2 ATP created but most energy transferred to NAD+ and FAD
• Is a closed loop bcuz last part of process reforms 1st molecule
• Turns two times for one molecule of glucose (one for each pyruvate)

Substrate Level Phosphorylation

• Glycolysis and Citric Acid Cycle make ATP this way
• Enzyme transfers phosphate from substrate molecule to ADP

OXIDATIVE PHOSPHORYLATION (electron transfer and chemiosmosis)

• Process of producing ATP from NADH and FADH2 as electrons give up energy used to phosphorylate ADP to ATP
• Occurs in the inner mitochondrial membrane of eukaryotes; plasma membrane of prokaryotes
• Cytochromes: proteins carriers, function in oxidative phosphorylation