Catabolism of Proteins and Lipids

Aerobic respiration cannot take place if there are not the genes to make the different components, if there are not the genes to protect the cell from the oxygen free radicals that are made in oxidative phosphorylation, or if there is not enough oxygen.

In anaerobic respiration, an inorganic molecule other than oxygen acts as the final electron receptor in the electron transport chain. This phenomenon is mainly seen in archaea and bacterial organisms. Some of these are those that use nitrate or nitrate, which are reduced to make nitrogen gas. The Krebs cycle is intact in these organisms but the electron transport chain is altered. These organisms are called denitrifiers.

The electron in the electron transport chain gradually loses energy with each pass; however, some of this energy is stored by pumping hydrogen ions across a membrane, which can be outside the cell in prokaryotic organisms. When this happens, there is potential energy created, which is also referred to as the proton motive force. It is more acidic on the outside of the membrane than the inside of the membrane. This potential energy can drive certain reactions, such as those involved in flagella rotation and those involved in the intake of nutrients.

The flow of hydrogen ions is called chemiosmosis. This force is made use of by an important enzyme called ATP synthase, which makes ATP. The flow of hydrogen ions back across the membrane drives the enzyme to make ATP. The actual number of ATP molecules made in the entire catabolic process varies. The average number is about 30 to 34 ATP molecules per glucose molecule. The maximum is about 38 molecules.

CATABOLISM OF PROTEINS AND LIPIDS

Other nutrients can be catabolized besides glucose. What happens when there are lipids or proteins that need to be broken down? It turns out that there are mechanisms in place to metabolize these sorts of molecules. Most of them ultimately feed into the glycolysis, transition reaction, or Krebs cycle in some way so it can progress similarly to glucose at the end of the catabolic process.

Triglycerides can be broken down and metabolized. There are lipases and phospholipases that start the process of degradation. Some organisms use these enzymes as part of their virulence because they can use the enzymes to catabolize the