Steps in the endocytosis of cholesterol. 
Low-density lipoproteins (LDL's) filled 
with cholesterol approach the cell (a) 
and attach to LDL receptors in the cell's 
surface membrane (b). After passing 
into the cell, a vesicle filled with LDL's 
joins with a smooth vesicle (c) to 
become an endosome (d), in which the 
LDL's and the LDL receptors pull apart. 
A vesicle filled with LDL's migrates to a 
lysosome (e), which breaks down the 
LDL's and releases free cholesterol into 
the cytoplasm (f). Meanwhile, the LDL 
receptors are returned to the cell 
surface (g). 
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