Nuclear envelope

The nuclear envelope separates the contents of the nucleus (ie, karyoplasm, chromatin fibrils, nucleolus) from the cytoplasm.

Structure

 * Inner membrane - towards the inside contains a reticular network of protein molecules of 3 types (condensed parts of chromatin fibrils adhere to them, this enables the spatial separation of individual chromosomes in the preparation for their replication.
 * Outer Membrane - transitions smoothly into the endoplasmic reticulum, ribosomes are often visible on it.
 * Between them is the perinuclear space' (connected to the reticular cistern system).

Nuclear pore

 * Octagonal openings, connecting the outer and inner membrane;
 * 80 nm in diameter;
 * the nucleus of a mammalian cell has 3000-4000;
 * lined with a complex of 24 protein molecules with a closing granule;
 * transports small protein molecules + large particles from the nucleus (ribosomal subunits, processed molecules mRNA);
 * transport in the nuclear pores is massive, therefore regulation is necessary, but it has not yet been fully elucidated.

Related Articles

 * Chromosome
 * Cell
 * Core