Fig. 12-16 Diagram showing autophagy
After an abnormal mitochondrion is packaged by a vesicle, it is degraded by an acid hydrolase that has been transported from the Golgi body.
Cells possess a mechanism for degrading abnormal organelles or substances in the cell (i.e., broken mitochondria or abnormally aggregated proteins) by themselves (Fig. 12-16). This function is called autophagy. Autophagy is the function where a substance to be degraded is packaged into a vesicle and an acid hydrolase brought over from the Golgi body enters the vesicle to degrade its contents. This type of autophagy not only degrades unnecessary entities but also plays a different targeted role. This role is to independently ensure the availability of critical nutrients and energy during cell starvation. In other words, cells that have been unable to obtain nutrients from the outside digest their own extraneous structures and temporarily use them as nutrition.