Chromosome Structure and Telomeres

These flashcards summarize key concepts related to chromosome structure, chromosome territories, the nature of euchromatin and heterochromatin, and the role of telomeres and telomerase in DNA replication.

Chromosome Territories

Regions specific to tissue types where actively transcribed genes are found.

Euchromatin

True chromatin that can change; contains genes that are actively transcribed or can be easily turned on.

Heterochromatin

Highly condensed and closed chromatin that is unexpressed, typically found in centromeres and telomeres.

Facultative Heterochromatin

Regions that can shift between heterochromatin and euchromatin; usually encompasses larger areas.

Telomere

The protective end of linear chromosomes, rich in guanine, crucial for stability.

Telomere Shortening

The phenomenon where telomeres shrink over a lifetime due to cell division, leading to potential issues in DNA replication.

Telomerase

An enzyme that extends telomeres by forming an RNA/DNA hybrid, allowing for the synthesis of additional DNA.

Lagging Strand Problem

The issue during DNA replication where gaps at the ends of telomeres are created, leading to their shortening.

Mutagens

Agents that can cause mutations, some of which may lead to longer telomeres in cancerous cells.

RNA Polymerases

Enzymes found in the channels of chromosome territories responsible for transcription.

Chromosome Structure

The organization of DNA and protein in chromosomes that allows for efficient packing and gene expression.

Gene Expression

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

Nuclear Envelope

The double-membrane structure that encloses the nucleus, separating it from the cytoplasm.

Histones

Proteins around which DNA winds to form nucleosomes, aiding in the compaction of DNA.

Nucleosome

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