Autophagy, the destruction of the cell's components by its own enzymes, is a process of all eukaryotic cells. Various types of autophagy occur during normal development or as a response to various types of stress, including starvation. Defects in autophagy are correlated with a number of diseases in humans. Recent advances in the study of autophagy in baker's yeast (Saccharomyces cerevisiae) have provided insight into the molecular basis of this process in more complex eukaryotes, including animals and humans.