Molecular Structure of Chromosomes and Transposable Elements

These flashcards cover terminology and concepts related to molecular structures of chromosomes and transposable elements.

Chromosome

A structure composed of DNA and protein, carrying genetic information.

Genome

The complete set of genes or genetic material present in a cell or organism.

Prokaryotic Chromosome

Typically circular, generally with a single type per cell, comprising a few million base pairs.

Supercoiling

The additional twisting of DNA strands beyond the natural coiling, which can be positive or negative.

Nucleoid-associated proteins (NAPs)

Proteins that facilitate chromosome organization and compaction in prokaryotes.

Nucleosome

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

Histone proteins

Basic proteins that package and order DNA into structural units called nucleosomes.

Transposable elements

DNA sequences that can change their position within the genome, sometimes causing mutations.

Simple transposition

A mechanism by which a transposon is removed from one location and inserted into another.

Retrotransposition

The process where a retrotransposon moves through an RNA intermediate, increasing its copy number.

SINEs

Short interspersed nuclear elements, a class of transposable elements in the genome.

LINEs

Long interspersed nuclear elements, another class of transposable elements present in the genome.

TADs (Topologically Associating Domains)

Regions in the genome that interact with one another more frequently than with outside regions.

Euchromatin

Less condensed chromatin that is actively involved in transcription.

Heterochromatin

Tightly packed regions of chromatin that are generally transcriptionally inactive.

Chromosome territories

Distinct regions within the nucleus where individual chromosomes are located during interphase.

Positive supercoiling

A condition where DNA is overwound, causing strain that can hinder replication and transcription.

Negative supercoiling

A condition where DNA is underwound, facilitating replication and transcription.