What are the sequence of events in cellular respiration?

1 Answer
Oct 7, 2015

In aerobic cellular respiration, first we have glycolysis, the citric acid cycle, and finally oxidative phosphorylation.


Aerobic cellular respiration can be broken down into three main steps: glycolysis, the citric acid cycle (the Kreb's cycle ), and electron transport.


  1. Glycolysis occurs in the presence of oxygen and is when glucose is broken down. This occurs in the cytoplasm. The result of glycolysis is two molecules of ATP , pyruvate, and NADH.

Before the second main step begins, the pyruvate undergoes oxidization in the mitochondria and is converted into Acetyl-CoA. NADH gains electrons and carbon is lost, which forms CO2.

  1. The second step is the citric acid cycle, which you can see in the image below.

Simplified diagram of citric acid cycle:

This complex cycle results in eight NADH, two FADH2, two ATP, and six CO2.

  1. The last main portion of cellular respiration is oxidative phosphorylation. Electrons from NADH and FADH2 are transferred through the membrane of the mitochondria. When hydrogen ions come back across the membrane, ATP is synthesized though what is called the ATP synthase complex.


This is a very good animation showing how energy is converted from glucose to energy.