General Structure and Function of Chromosomes

A comprehensive set of flashcards covering key vocabulary terms and definitions related to the general structure and function of chromosomes, suitable for exam preparation.

Genome

The hereditary basis of every living creature, containing all the information in an organism's DNA.

Eukaryotic genome

Consists of linear double-stranded DNA and organelle DNA.

Heterochromatin

Tightly packed DNA region, rich in A-T, appearing dark with specific dyes.

Euchromatin

Loosely packed DNA region, rich in G-C, appearing pale with specific dyes.

Homolog chromosomes

Pairs of chromosomes inherited from each parent, one maternal and one paternal.

Aneuploidy

An abnormal number of chromosomes in a cell, leading to disorders.

Centromere

Region of a chromosome where sister chromatids are joined and spindle fibers attach.

Telomere

Repeated sequences of DNA that protect the ends of chromosomes.

Chromosome placement

Arrangement of chromosomes within the nucleus during interphase.

Autosomes

Non-sex chromosomes, with humans having 44 autosomes.

Metacentric chromosomes

Chromosomes with centromeres positioned in the middle, resulting in equal arms.

Submetacentric chromosomes

Chromosomes with centromeres not exactly at the center, leading to unequal arms.

Acrocentric chromosomes

Chromosomes with centromeres near one end.

Telocentric chromosomes

Chromosomes with centromeres at the end, which are not present in the human genome.

Exons

Coding sequences in a gene that specify amino acids.

Introns

Non-coding sequences in a gene that are removed during RNA processing.

Gene-rich regions

Parts of the genome with a higher concentration of genes, often located centrally.

Gene-poor regions

Areas of the genome with fewer genes, usually situated at the periphery.

Sister chromatids

Identical copies of a chromosome connected by the centromere.

Replication origin

Regions in the genome where DNA replication initiates.

Chromatin

The complex of DNA and proteins that forms chromosomes in eukaryotic cells.

Histoned proteins

Basic proteins that contribute to the structure of chromatin.

Non-histone proteins

Proteins that assist in chromosome structure and function.

Nucleosome

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

Chromatin condensation

The process of packaging chromatin into a more compact structure.

30 nm fiber

The structure formed by the coiling of nucleosomes, resulting in a thicker chromatin fiber.

Chromosome sizes in humans

Range from 45 Mb to 279 Mb for different chromosomes.

Eukaryotic cell cycle

The process where DNA replicates and chromosomes duplicate before cell division.

Kinetochore

A protein complex at the centromere that binds to microtubules during cell division.

Mitosis

The division of a eukaryotic cell nucleus resulting in two daughter cells with identical genetic material.

Meiosis

A specialized form of cell division that reduces chromosome number by half, producing gametes.

G-T rich extension (G-tail)

The single-stranded extension of telomeres composed of guanine and thymine.

Chromosome classification

Categorizing chromosomes based on the position of their centromeres.

Nuclear DNA

The DNA contained within the nucleus of eukaryotic cells.

Chromosome idiograms

Visual representations of the number and appearance of chromosomes in an organism.

Condensation hierarchy

The multi-step process of chromatin packaging within the nucleus.

Histone core

An octamer of histone proteins around which DNA is wrapped in a nucleosome.

Scaffold proteins

Proteins that help maintain the structural organization of chromosomes.

High-mobility group proteins (HMG)

Proteins involved in processes like DNA repair and chromosome structure.

Salt bridges in histones

Interactions that help stabilize the binding of DNA to histone proteins.

Hydrogen bonds in nucleosomes

Forces that maintain the structure of nucleosomes between DNA and histones.

Nucleosome formation

The initial stage of chromosomal structure development.

Solenoid structure

The coiled arrangement of chromatin fibers forming a 30 nm fiber.

Chromatin fiber formation

The process of nucleosomes folding into higher-order chromatin structures.

Centromeric DNA

DNA found at the centromere, rich in A-T sequences.

Alpha-satellite DNA

Repetitive DNA sequences found in the centromeres of human chromosomes.

Pericentromeric heterochromatin

Regions of heterochromatin surrounding the centromere.

Mitochondrial DNA

DNA contained within mitochondria, separate from nuclear DNA.

Genome variation

Differences in chromosome number or structure between related species.

Chromosome segregation

The process by which chromosomes are separated into daughter cells.

Kinetochore microtubules

Microtubules that connect kinetochores to spindle poles during cell division.

Gene regulation

The process by which genes are turned on or off in response to signals.

Eukaryotic transcription

The process of copying DNA sequences into RNA in eukaryotic cells.

Stress response of telomeres

How telomeres protect chromosomes from damage under stress.

Nuclear localization of chromosomes

The specific arrangement of chromosomes within the nucleus.

Chromosome damage protection

Mechanisms that safeguard chromosomes against physical harm.

Centromere functions

Roles played by centromeres in chromosome stability and segregation.

Gene expression timing

The precise control of when and where genes are expressed in cells.

Telomerase

An enzyme that extends the telomeres of chromosomes during replication.

Chromatin remodeling

Dynamic changes in chromatin structure allowing access to DNA.

Chromosomal anomalies

Abnormalities in chromosome number or structure affecting health.

Female sex chromosomes

XX configuration in humans indicating biological females.

Male sex chromosomes

XY configuration in humans indicating biological males.

Cellular differentiation

The process through which cells become specialized in structure and function.

Aberrant chromosomal division

Improper separation of chromosomes during cell division.

Polyploidy

The condition in which a cell has more than two paired (homologous) sets of chromosomes.

Gestational age and chromosomes

The relationship between an organism's development and chromosomal integrity.

Genetic diversity from chromosomes

How varying chromosome structure influences genetic variation.

Chromosomal fusion

Joining of two chromosomes which can lead to genetic disorders.

Gene amplification

Excessive replication of one or more genes found on chromosomes.

Chromosomal inversions

Rearrangements of chromosome structure where segments are reversed.

Microdeletion syndrome

Disorders resulting from small deletions of chromosome segments.

Chromosome translocation

The transfer of chromosome segments between non-homologous chromosomes.

Genome mapping

The method of determining the location of genes on a chromosome.

Nuclear envelope dynamics

Changes in the nuclear envelope during cell cycle and division.

Cellular aging and telomeres

How telomere length affects the lifespan of cells.

Chromosomal stability

The maintenance of chromosome integrity during cell division.

Centromere differentiation

The formation of specialized centromeric regions in chromosomes.

Stem cell chromosome dynamics

Variations in chromosomes observed in stem cells versus differentiated cells.

Cytogenetics

The field of biology that studies chromosomes and their role in genetics.

Molecular mechanisms in chromatin

Processes regulating the function and structure of chromatin.

Cell growth regulation

Control mechanisms that determine cellular expansion and division.