List the three subpathways of cellular respiration and the r

List the three subpathways of cellular respiration and the results of each.

Solution

The 3 subpathways of cellular respiration are as follows:

1. Glycolysis followed by link reaction: Take place in the cytoplasm and results in one glucose molecule being converted into two pyruvate molecules with a net yield of 2 ATP molecules. Two NAD+ which act as hydrogen carriers are converted into NADH + H+
The link Reaction: Pyruvate from glycolysis is absorbed by the mitochondion. Pyruvate undergoes oxidative decarboxylation, whereby hydrogen is removed to form NADH + H+, and carbon dioxide is removed. The end result is an acetyl group, which is accepted by coenzyme A to form Acetyl CoA.

2. Krebs cycle: Acetyl group is transferred from Acetyl CoA to oxaloacetate at the beginning of the cycle to form a 6-carbon compound. The compound undergoes oxidative decarboxylation, which is distributed through 6 reactions : 2 reactions result in CO2 and the remaining four result in H+. Of the H+ produced, that from three of the four reactions goes to form NADH + H+ and the remaining forms FADH2. ATP is also produced in one of these reactions and is termed a substrate-level phosphorylation.

3. ETC (Electron Transport chain): is a series of electron carriers located in the membrane of the mitochondia. NADH + H+ and FADH2 give their electrons to these carriers in the membrane, which then \"carry\" the electron from one carrier to another. The elctron is losing enery as it is passed from one carrier to another. While this is taking place, the concentration of H+ outside the mitochondia is growing larger and larger and so must be fixed. The energy released as electron pass along the transport chain is used to pump H+ accross the membrane of the mitochondia. The flow of the H+ ions through an enzyme known as ATP synthase drives the enzyme to produce ATP. At the end of ETC, the electrons are given to oxygen, which also accepts excress hydrogens, to form water.