The Nucleus

• Round or oval organelle present in both plant and animal cells.
• Comprises a nuclear membrane with small pores controlling substance entry and exit.
• Inside the nucleus is the cytoplasm, nucleoplasm.
• The nucleolus contains RNA.
• The chromatin network carries the organism's hereditary characteristics.
• Functions include controlling cell activities and carrying hereditary traits.

A histological sample showing a number of nuclei is provided below:

A Transmission Electron Micrograph of a nucleus.