Smooth E.R. (1 of 3) |
|  | The endoplasmic reticulum is a series of double membranes that loop back and forth between the cell membrane and the nucleus. These membranes fill the cytoplasm but you cannot see them because they are very transparent. There are two distinct types of E.R.: The rough E.R. has ribosomes and is the site of protein synthesis; the smooth E.R. has no ribosomes. Cut the E.R to get a better look at both types, then zoom in and click next. Cut the E.R... |