Nucleus

Definition

The nucleus is a membrane-bound organelle found in eukaryotic cells that houses the cell's genetic material. It plays a crucial role in regulating gene expression and maintaining the integrity of DNA.

5 Must Know Facts For Your Next Test

1. The nucleus contains most of the cell's genetic material in the form of chromatin, which condenses into chromosomes during cell division.
2. It is surrounded by a double membrane called the nuclear envelope, which features nuclear pores for transport of molecules.
3. The nucleolus, located within the nucleus, is responsible for ribosome synthesis and assembly.
4. Nuclear DNA is organized with histone proteins to form nucleosomes, facilitating efficient packaging and regulation.
5. The nucleus coordinates cellular activities such as growth, metabolism, protein synthesis, and reproduction by controlling gene expression.

Review Questions

• What are the main functions of the nucleus in eukaryotic cells?
• How does the nuclear envelope contribute to nuclear function?
• What role does the nucleolus play within the nucleus?

Related terms

Chromatin:

A complex of DNA and protein found in eukaryotic cells that packages DNA into a more compact form.

Nuclear Envelope:

A double membrane structure surrounding the nucleus, containing pores for molecular transport.

Nucleolus: A dense region within the nucleus responsible for ribosomal RNA synthesis and ribosome assembly.