cells

structure of nucleus

largest organelle, easily seen under light microscope. enclosed by nuclear envelope. contains genetic information in the form of chromosomes. hereditary information is stored in DNA.

functions of nucleus

storage of DNA. site of RNA synthesis. controls cell activities such as cell growth and cell repair.

structure of RER

comprises a network of flattened spaces lined with a membrane. outer surface of membrane is continuous with the nuclear membrane. surface appears rough as ribosomes are attached to the outer surface.

function of RER

site of synthesis of proteins for secretion or incorporation into membranes. facilitation of folding of polypeptide chain.

structure of SER

network of tubules. lacks ribosomes attached to a membrane

function of SER

synthesis of lipids, converts harmful substances into harmless substances through detoxification