Chromatin

Definition

Chromatin is a complex of DNA and proteins found in the nucleus, which condenses to form chromosomes during cell division. It plays a critical role in regulating gene expression and DNA replication.

5 Must Know Facts For Your Next Test

1. Chromatin consists of DNA wrapped around histone proteins, forming nucleosomes.
2. There are two main types of chromatin: euchromatin (less condensed and transcriptionally active) and heterochromatin (more condensed and transcriptionally inactive).
3. Post-translational modifications of histones, such as methylation and acetylation, influence chromatin structure and gene expression.
4. Chromatin remodeling is essential for processes like replication, repair, and transcription.
5. The organization of chromatin affects the accessibility of genetic information.

Review Questions

• What are the two main types of chromatin?
• How do post-translational modifications affect chromatin?
• What role does chromatin play in gene expression?

Related terms

Nucleosome:

A structural unit of chromatin consisting of a segment of DNA wound around eight histone proteins.

Histone:

A protein that provides structural support to a chromosome; DNA wraps around histones to form nucleosomes.

Euchromatin:

A less condensed form of chromatin that is generally transcriptionally active.