Is macroautophagy a selective degradation process?
Yes. Macroautophagy (commonly referred to simply as autophagy) is a catabolic process conserved throughout the eukaryotes, and is distinct from other forms of autophagy by the formation of the autophagosome: this is a vesicle-like formation surrounded by a double membrane that sequesters the cytoplasmic material to be degraded. It was initially considered that macroautophagy was a bulk process; however, recent findings illustrate that specific cargos (ranging from misfolded or excess proteins, to organelles or even bacterial cells) can be selectively targeted to the pre-autophagosome membrane (i.e. the phagophore) and finally to the vacuoles/lysosomes for their degradation.