Moving towards the nucleus we pass by layers of internal membranes The nucleus is enclosed by a double membrane called the nuclear envelope Let's enter the nucleus through a pore The nucleus houses the genetic material of the cell - DNA which carries the blueprints for making the cells proteins Almost two meters of DNA is crammed inside the nucleus How does it all fit? The DNA is wrapped around proteins like thread wrapped around spools Look, this section of the DNA has unwound and a different protein has attached to the DNA DNA is being used a a template to make mRNA mRNA molecules travel from the nucleus to the cytoplasm carrying the instructions for making specific proteins In the cytoplasm a ribosome clamps onto a strand of mRNA The ribosome ratchets along the mRNA building a new protein Some proteins stay in the cytoplasm Others, like this one are processed in special compartments within the cell