<Table> <Tr> <Th_colspan="2"> Cell biology </Th> </Tr> <Tr> <Td_colspan="2"> The animal cell </Td> </Tr> <Tr> <Td_colspan="2"> Components of a typical animal cell: <Ol> <Li> Nucleolus </Li> <Li> Nucleus </Li> <Li> Ribosome (little dots) </Li> <Li> Vesicle </Li> <Li> Rough endoplasmic reticulum </Li> <Li> Golgi apparatus (or "Golgi body") </Li> <Li> Cytoskeleton </Li> <Li> Smooth endoplasmic reticulum </Li> <Li> Mitochondrion </Li> <Li> Vacuole </Li> <Li> Cytosol (fluid that contains organelles, comprising the cytoplasm) </Li> <Li> Lysosome </Li> <Li> Centrosome </Li> <Li> Cell membrane </Li> </Ol> </Td> </Tr> </Table> <Tr> <Th_colspan="2"> Cell biology </Th> </Tr> <Tr> <Td_colspan="2"> The animal cell </Td> </Tr>

What is the main function of endoplasmic reticulum