Genetic Material and Chromatin Structure

These flashcards cover key vocabulary and concepts related to genetic material and chromatin structure as discussed in the lecture.

Chromatin

A complex of genetic material (DNA) and proteins (histones) that packages DNA into a compact structure.

Euchromatin

A type of chromatin that is loosely packed and accessible for transcription; contains active genes.

Heterochromatin

A type of chromatin that is tightly packed and generally inaccessible for transcription; contains inactive genes.

Nucleosome

The basic unit of DNA packaging, consisting of a segment of DNA wound around a core of histone proteins.

Histones

Proteins that help package and condense DNA into chromatin.

Facultative heterochromatin

Chromatin that can switch between euchromatin and heterochromatin states based on the needs of the cell.

Constitutive heterochromatin

Chromatin that is permanently in a heterochromatin state and typically contains non-coding regions.

Solenoid model

A proposed structure of chromatin in which nucleosomes are coiled into a 30 nm fiber, resembling a solenoid.

Zigzag model

An alternative model of chromatin packing in which nucleosomes are arranged in a zigzag formation, allowing for less sharp bends in the DNA.

Supercoiling

The further twisting of DNA upon itself, which occurs during chromatin condensation.

Meiosis

A specialized type of cell division resulting in four gametes with half the number of chromosomes.

Mitosis

A process of cell division that results in two genetically identical daughter cells.

Interphase

The phase of the cell cycle where the cell prepares for division, occurring before mitosis.

Metaphase chromosome

The most condensed form of chromatin observed during metaphase, allowing for proper segregation during mitosis.

Gene expression

The process by which information from a gene is used to synthesize functional gene products, typically proteins.

Transcription

The process of copying a segment of DNA into RNA.

Centromeres

The region of a chromosome where the two sister chromatids are joined and where the spindle fibers attach during cell division.

Telomeres

The repetitive DNA sequences at the ends of linear chromosomes that protect them from degradation.

DNA replication

The process by which a DNA molecule is copied to produce two identical DNA molecules.

Cellular DNA Content

The total amount of DNA present in a cell, typically organized into chromosomes.