The nuclear envelope performs the following functions :

1. It maintains the shape of the nucleus.

2. It keeps the nuclear contents in place and distinct from the cytoplasm.

3. It regulates the flow of materials into and out of the nucleus by active transport and outpocketing.

4. Its pores allow the exit of ribosomal subunits.

Functions of nuclear matrix :

1. It maintains the shape of the nucleus.

2. Chromatin fibres are anchored to nuclear matrix.

3. The machinery for various nuclear activities such as transcription and replication is associated with the matrix.

Functions of nucleolus :

1. It is the site for rRNA synthesis.