 the nucleus nuclear envelope first the contents nuclear envelope structure of nuclear envelope and the nuclear pores so first the nuclear envelope so if we want to define nuclear envelope is basically the outermost boundary of nucleus it is a double membrane structure and it separates nuclear material from the cytoplasmic material in simple words we can say that a nuclear membrane is nucleus's outermost boundary is double membrane structure means the cell membrane is single membrane structure nucleus has two membranes outer and inner nuclear membranes and second one it is separating nuclear material the material inside the nucleus will separate it from cytoplasm so what is the structure of nuclear envelope nuclear envelope if we study it structurally there are two membranes of nuclear envelope outer nuclear membrane and the inner nuclear membrane outer nuclear membrane it is connected with the endoplasmic reticulum so the endoplasmic reticulum's characters are almost on the outer nuclear membrane like presence of ribosomes ribosomes even on the outer nuclear membrane like the endoplasmic reticulum the inner nuclear membrane is separated from the outer nuclear membrane the inner nuclear membrane is completely different from the outer there is a space between the two and it is not directly connected the inner nuclear membrane is actually touching the nucleus environment whereas the outer nuclear membrane is touching cytoplasm the connection between the outer and the inner nuclear membrane is only connected to the nuclear pores so on the position of the nuclear pores the outer and the inner nuclear membrane are directly connected otherwise they are separated from each other so nuclear pores the important structure of nuclear envelope is the nuclear pore nuclear pore is actually responsible for transport of material from nucleus to cytoplasm the transport of material is basically due to the nuclear pores if we look at the nuclear pores it is a very dynamic structure it is simple to control the transport of material dynamic means that the size is very specific some of the material they can move from nucleus to cytoplasm other can move from cytoplasm to the nucleus for example, there are histone proteins in cytoplasm and then they are transported into the nucleus in such a nucleus, ribosomes and messenger RNA are formed and these two things go into cytoplasm such as nucleus nuclear pore is facilitating the transport of material but nuclear pore is not so large that DNA can move out of it that's why chromosomes are always in the nucleus when small molecules or other molecules can move outside then the structure of nuclear pore if we look at it from the outer and inner nuclear membrane the black area between the outer and the inner nuclear membrane is showing that both the nuclear membrane are separate only on the position of the nuclear pore they are linked to each other they are connected if you look closely at the structure of the nuclear pore we can see different types of material these are the proteins that make the nuclear pore some proteins that make the nuclear pore are globular proteins and some of them are the filamentous polyurethane filamentous means that they make thread-like structures so globular and filamentous proteins together make a structure of the nucleus nuclear pore is a very complex structure that's why we usually call it simple nuclear pore can we call it nuclear pore complex