With the imbibition of water, the hormone signal in barley, gibberellic acid (GA), is carried from the embryo to the aleurone layer of the endosperm. The GA activates the DNA for the gene encoding alpha-amylase in the aleurone cells. Transcription and translation of that gene results in the production of alpha-amylase inside the aleurone cells. This enzyme is shipped by ER into the Golgi, sorted and packaged into vesicles, and exported through the cell membrane by exocytosis. The amylase is thus dumped into the endosperm area. There the amylase breaks down starch into the sugar maltose which is transported to the embryo. The sugar fuels respiration in the embryo so it can grow. The radicle protrudes from the seed coat, and germination is accomplished. After plant physiologists figured this out, we could easily tell the brewing industry how to produce more beer per bushel of barley