Question

What is the sequence of events in cellular respiration?

Answer 1

All living beings need to metabolize and create energy in the form of ATP(Adenosine TriPhosphate) and the process by which this occurs is known as cellular respiration. Most eukaryotic organisms use aerobic respiration which means that they use oxygen for this process. Some simple organisms can use anaerobic respiration or respiration without oxygen.

Complete answer:
This respiration takes place in the cytosol and the mitochondria of the cell. The primary purpose of cellular respiration is to produce ATP which can then be used as energy by the body. The first step of this respiration starts in the cytosol where glycolysis occurs.
Glycolysis: The meaning of the word glycolysis is to break down glucose. Therefore glucose gets broken down into pyruvate and eventually, pyruvate gets oxidized into acetyl CoA. This step produces 2 ATP.
Citric Acid Cycle: Also known as the Krebs Cycle, the starting material for this cycle is acetyl CoA which gets broken down through many reactions into carbon dioxide. At the end of this cycle, multiple ${NAD}^{+}$ and ${FAD}^{+}$ get converted into NADH, and ${FADH}_{2}$ respectively which act as electron carriers.
Electron Transfer Chain: Over here oxidative phosphorylation occurs and NADPH and ${FADH}_{2}$ go through the electron transfer chain which has many different membrane channels. At the end of this process around 34 ATP is formed. This occurs in the mitochondria which is why it is called a powerhouse of the cell.

Note:
The first step of this process is the breaking down of glucose into pyruvate and the oxidation of pyruvate into acetyl CoA. Next acetyl CoA goes into the citric acid cycle which gets broken down to make NADH and ${FADH}_{2}$ and finally these molecules enter the electron transport chain which produces around 34 ATP molecules.