Endomembrane system
...lasmic reticulum is an extensive network of membranes that extends from the cell membrane through the cytoplasm to the nuclear membrane. The membranes of the ER enclose a series of tubes and flattened membranous areas. There are two types of ER, smooth ER has no ribosomes on it and rough ER which has large numbers of ribosomes on it. The basic function of ER is transportation. The proteins produced by the ribosomes are transported to regions of the cell where they are need or they are transported to the Golgi body for export from the cell. The Golgi apparatus also known as the Golgi body is similar to endoplasmic reticulum. The Golgi apparatus consists of sacs which are stacked like pancakes. The function of Golgi apparatus is really two things. The First is the modification of lipids and proteins. The Second function is storage and packaging of materials that will be exported from the cell. The Golgi apparatus is also known as the shipping department of the cell. The vesicles that pinch off from the Golgi apparatus move to the cell membrane and the material in the vesicle is released to the outside of the cell. Some of these pinched off vesicles also become lysosomes. Lysosomes are sacs containing digestive enzymes that are surrounded by a single. membrane. Lysosomes are used by the cell to digest or breakdown most complex organic molecules. The Lysosomes digest can either digest substances brought into the cell or they can digest parts of the cell itself. Cells that eat other cells surround the ingested cell with a membrane forming a food vacuole. This food vacuole is then fused with a lysosome and the cell is digested. Vacuoles are surrounded by membranes. They are sort of like a storage bubble in the cytoplasm. In animal cells vacuoles may store food that needs to be digested. Food cannot pass through membranes until it is broken into smaller particles. The lysosome can fuse with the vacuole membrane and squirt digestive The plasma membrane ...