DNA, Chromosomes, and the Nucleus

These flashcards encompass key vocabulary terms and concepts related to DNA, chromosomes, and the nucleus, aiding in the revision and understanding of genetic material.

DNA (Deoxyribonucleic Acid)

A molecule that carries genetic information used in the growth, development, functioning, and reproduction of all living organisms and many viruses.

Chromosomes

Structures within cells that contain DNA wrapped around histone proteins, ensuring DNA is compacted and organized for cell division.

Nucleus

A membrane-bound organelle in eukaryotic cells that contains the cell's genetic material.

Avery's Experiment

A scientific experiment that identified DNA as the transforming substance in bacteria, proving that DNA is the genetic material.

Bacteriophage

A type of virus that infects bacteria, used in experiments to demonstrate that DNA is the genetic material.

Supercoiling

The over-winding or under-winding of a DNA strand, affecting its structure and functionality.

Nucleosome

The basic unit of DNA packaging in eukaryotes, composed of a segment of DNA wound around a core of histone proteins.

Euchromatin

A less condensed form of chromatin that is actively involved in transcription and gene expression.

Heterochromatin

A tightly packed form of DNA that is generally inactive in terms of gene expression.

Centromere

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

Telomeres

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

Chargaff's Rules

The observation that, in DNA, the amount of adenine (A) equals that of thymine (T), and the amount of guanine (G) equals that of cytosine (C).

DNA Replication

The biological process of producing two identical replicas of DNA from one original DNA molecule.

RNA

Ribonucleic acid, a molecule essential for various biological roles, including coding, decoding, regulation, and expression of genes.

Positive Supercoil

A supercoiling of DNA that results from twists in the same direction as the helix.

Negative Supercoil

A supercoiling of DNA where the DNA is twisted in the opposite direction of the helical twist.

DNA Denaturation

The process of separating the two strands of the DNA double helix, typically achieved by heat or pH changes.

DNA Renaturation

The process by which denatured DNA strands re-anneal to form a double helix structure.

Histones

Basic proteins around which DNA is wrapped to form nucleosomes, playing a key role in DNA packaging.

Transcription

The process by which the genetic information encoded in DNA is copied into messenger RNA.

Topoisomerase

An enzyme that alters the supercoiled form of DNA, playing a critical role in DNA replication and transcription.