Fill in the Blanks Below with Single Words

Essay

Fill in the blanks below with single words.
_____1_____ is an important natural process that is devoted to eliminating diseased or potentially harmful deviant cells. There are two classes of pathways. In one of these neighboring cells deliver signals that are received by ____2____ on the surface of those cells selected to undergo ____1____. Other pathways, such as the mitochondrial ____1____ pathway, respond to certain types of ____ 3____damage (such as that caused by harmful ____4_____ ____5_____ species or exposure to dangerous levels of _____6_____ radiation). In most cases the _____1______ pathway ends by inducing the cell to produce a class of proteolytic enzymes known as _____7_____. ____7_____ are the cell's executioners: they inactivate all kinds of important proteins in the cell, and they release an _____8______ that cleaves DNA into small fragments. Because each of our cells has the potential to commit suicide, the pathways of _____1_____ need to be tightly regulated.