BMS 250 Chapter Notes - Chapter 4: Cytoplasmic Streaming, Globular Protein, Endocytosis
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As in the er, a signal sequence may be added. The golgi also synthesizes its own molecules including long, unbranched polysaccharides, which are modified with the addition of small amounts of proteins to form proteoglycans. At the trans-face, secretory vesicles form and carry both the modified and newly formed molecules away from the golgi apparatus for different fates. Some secretory vesicles become components of the plasma membrane and others release their contents from the cell into the interstitial fluid by exocytosis. Thus, the golgi is especially extensive and active in cells specialized for protein, glycoprotein, and proteoglycan secretion: vesicles released from the trans face of the golgi may also contain hydrolytic digestive enzymes required for lysosomes. Lysosomes: are small, membranous sacs that contain digestive enzymes, which are immersed in acidic fluid. These enzymes are contributed to lysosomes as portions of the golgi containing digestive enzymes pinch off to form vesicles, and these vesicles then fuse with the lysosome.
