Question

Why do biologists believe glycolysis evolved before the krebs cycle and the electron transport chain?

Answer 1

Answer:

Glycolysis evolved before Kreb's cycle and Electron Transport chain. This view is supported by following facts:

• Glucose cannot enter the mitochondria and it needs to be broken  down into pyruvate in the cytosol by the process of glycolysis.
• Pyruvate then forms acetyl CoA that enters the mitochondria where it undergoes Kreb's cycle.

• The Electron transport Chain occurs by passing of electron and finally donating it to the electron acceptor oxygen. The molecules of NADH  produced in the preparatory phase of glycolysis provides the electron for electron transport chain.

• Thus Glycolysis must have evolved before Kreb's Cycle and Electron Transport Chain otherwise the raw materials for both the processes would not have been available.