LONG before the green movement existed, evolution discovered the virtues of recycling. Cells cannot afford to waste materials, so they disassemble worn-out components for reuse. This happens in subcellular structures called lysosomes, which are bubble-like vesicles filled with digestive enzymes and surrounded by fatty membranes.
Moreover, in an emergency, even components that are still working may be recycled in this way to provide energy needed to keep a starving cell alive, rather as someone facing extremely cold weather may choose to burn his furniture rather than freeze to death. The process is called autophagy (from the Greek for “self-eating”), and the elucidation of its details has been the life’s work of Yoshinori Ohsumi of the Tokyo Institute of Technology (pictured above), who is the winner of this year’s Nobel prize for physiology or medicine.
Before Dr Ohsumi’s studies, biologists knew that autophagy was a two-step process. First, the cellular components to be recycled are enclosed in a fatty membrane to create another type of vesicle, an autophagosome. Then the autophagosome merges with a lysosome, and the…Continue reading
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