CH 12 Chromosome Structure

A collection of vocabulary flashcards related to chromosome structure and function.

Nucleic acid

The genetic material of viruses, which can be either DNA or RNA.

Capsid

The protein coat that surrounds and protects the viral nucleic acid.

Envelope

A lipid membrane that surrounds some viruses outside the protein coat.

Virion

The complete virus particle consisting of nucleic acid and a capsid.

Prokaryote

An organism whose cells lack a nucleus, such as bacteria.

Supercoiling

The coiling of DNA that occurs to compact it for storage within a small volume.

Chromatin

The complex of DNA and protein found in the nucleus; it exists in decondensed or condensed forms.

Eukaryotic chromosome

Chromosomes composed of double-stranded DNA that are organized into distinct structures.

Histone proteins

Positively charged proteins that bind DNA, playing a role in chromatin structure.

Nucleosome

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

Telomeres

The ends of eukaryotic chromosomes that protect them from degradation.

Telomerase

An enzyme that extends telomeres by adding repetitive sequences to their ends.

Heterochromatin

Chromatin that is densely packed and typically transcriptionally inactive.

Euchromatin

Loosely packed chromatin that is generally active in transcription.

Centromere

The constricted region of a chromosome that holds sister chromatids together and serves as an attachment site for spindle fibers.

Cohesin

A protein complex that holds sister chromatids together throughout cell division.

Nucleoid

The region of prokaryotic cells where the DNA is located, not enclosed by a membrane.

Plasmids

Small circular DNA molecules found in prokaryotes that can replicate independently of chromosomal DNA.

Gene expression

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

DNA gyrase

An enzyme that introduces negative supercoils into DNA, aiding in its compaction.

Transcription factors

Proteins that help regulate the transcription of genes by binding to nearby DNA.

Chromosomal bands

Patterns formed on chromosomes when stained; useful for locating genes.

Kinetochore

A protein complex that assembles at the centromere and facilitates attachment to spindle fibers.

Histone acetylation

The addition of acetyl groups to histones, which generally enhances gene expression by loosening DNA structure.

Histone methylation

The addition of methyl groups to histones, which can either activate or repress gene expression depending on the specific amino acid modified.

Hybridization

The process of pairing complementary DNA strands to determine gene locations.

Nuclease digestion

The breakdown of DNA by nucleases, often used to study chromatin accessibility.

Condensins

Protein complexes that help compact chromosomes into higher-order structures during mitosis.

G-banding

A technique used to stain chromosomes and visualize banding patterns for genetic analysis.

Giemsa stain

A dye used in staining chromosomes to reveal distinct banding patterns.

DNA replication

The process of copying DNA for cell division, ensuring each daughter cell receives an identical set of genetic material.