Chromosomes and Karyotypes

Educational flashcards covering the fundamental concepts of chromosomes, including prokaryotic vs. eukaryotic structures, ploidy, and karyotype analysis based on IB Biology standards.

Chromosomes

Structures that contain genes shared by the members of the same species.

Prokaryotic Chromosome

A chromosome consisting of a circular molecule of $ADN$ (DNA).

Plasmids

Small, additional molecules of $ADN$ (DNA) that contain genes useful for the cell (such as antibiotic resistance) but are not necessary for basic processes.

Eukaryotic Chromosomes

Linear molecules of $ADN$ (DNA) associated with histone proteins.

Genes

Small sections of chromosomes that code for the production of different proteins, which are later translated into different phenotypes or traits.

Sister Chromatids

Two identical molecules of $ADN$ (DNA) produced by replication.

Centromere

The location where two sister chromatids join together; its position can range from one end to the center of the chromosome.

Homologous Chromosomes

Chromosomes that have the same sequence of genes but not necessarily the same alleles of those genes.

Haploid Nucleus

A nucleus that has one chromosome of each pair; in humans, these contain $23$ chromosomes.

Gametes

Sexual cells, such as the ovum and sperm, that possess haploid nuclei and fuse during sexual reproduction.

Diploid Nucleus

A nucleus that has two chromosomes of each type, representing two complete sets of the chromosomes found in the species; in humans, these contain $46$ chromosomes.

Chromosome Number

A characteristic trait of the members of a species; organisms with different numbers of chromosomes are unlikely to be able to interbreed.

Sex Chromosomes

The pair of chromosomes ($23$ in humans) that determine the sex of an individual, such as $X$ and $Y$.

Autosomes (Somatic Chromosomes)

Chromosomes that do not determine sex; in humans, these are chromosome pairs $1$ through $22$.

Karyogram

An image of the chromosomes of an organism arranged in homologous pairs of decreasing length.

Karyotype

The description of the specific number and type of chromosomes present in an organism; a normal human karyotype shows $46$ chromosomes in $23$ pairs.

Down Syndrome (Trisomy 21)

A chromosomal anomaly where there are three copies of chromosome $21$ instead of two.

Turner Syndrome (Monosomy X)

A chromosomal anomaly characterized by the total or partial absence of the $X$ chromosome.

Klinefelter Syndrome

A chromosomal anomaly designated as $XXY$.