Nucleosomes, Histones, and Chromatin

Vocabulary flashcards summarizing key terms and definitions related to nucleosomes, histones, and chromatin as discussed in the lecture.

Histone

A type of protein that helps package and order DNA into structural units called nucleosomes.

Nucleosome

The fundamental unit of chromatin, consisting of a segment of DNA wrapped around a core of histone proteins.

Chromatin

Complex of DNA and proteins, primarily histones, that forms chromosomes within the nucleus of eukaryotic cells.

30-nm Fiber

A higher order of chromatin folding that forms a structure with a diameter of 30 nm, resulting from the compaction of nucleosomes.

Histone Code

The hypothesis that specific combinations of histone modifications can influence gene expression and transcriptional activity.

Acetylation

The addition of an acetyl group to a molecule, such as histone proteins, which often correlates with increased gene expression.

Deacetylation

The removal of acetyl groups from molecules, typically reducing transcriptional activity by condensing chromatin structure.

Heterochromatin

A dense form of chromatin that is transcriptionally inactive and typically found at telomeres and centromeres.

Euchromatin

A less condensed form of chromatin that is transcriptionally active and accessible to transcription machinery.

Transcription Factor

Proteins that bind to specific DNA sequences to regulate the transcription of genetic information from DNA to messenger RNA.