Cell Nucleus
The nucleus is the Control center of the cell.
Nuclear Envelope
Covers the nucleus.
Made up of two layers: an outer membrane and an inner membrane.
Outer Membrane
Contains ribosomes.
Continuous with the membrane of the rough endoplasmic reticulum.
Space in between two layers is continuous with the lumen of the rough endoplasmic reticulum.
Inner Membrane
Is smooth.
The inner and outer membrane meet at nuclear pores.
Nuclear Pores
The pathway between the inside of the nucleus and cytoplasm. For example for the exit of RNA and for entry of signal molecules.
Lined by nuclear pore complexes.
Nuclear Pore Complexes
Complexes of proteins.
Provide permeability selectivity to the pores.
Prevents the mixing of proteins on the inner and outer membranes.
Content of the Nucleus
Nucleoplasm
Equivalent to cytoplasm outside the nucleus.
DNA
The genetic information.
Spread in form of chromatin.
Takes the form of chromosomes when the cell divides.
Nucleolus
Accumulation of RNAs and proteins similar to ribosomes.
There can be one or more nucleoli in a nucleus.
Nuclear Lamina
Fibrillar protein skeletal near the inner membrane of the nuclear envelope.
Provides structural support to the nuclear envelope.
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Next, we will see the endoplasmic reticulum, the site of protein synthesis, and many metabolic reactions.