hromosomas

Hromosomas are thread-like structures inside cells that carry genetic material in the form of deoxyribonucleic acid (DNA). In eukaryotic organisms, hromosomas are located mainly in the cell nucleus, where they organize and protect genetic information that guides development, growth, and function. In many prokaryotes, the genetic material is stored in a single, circular chromosome within the nucleoid region, with additional small DNA molecules called plasmids in some species.

Each hromosoma consists of DNA tightly packaged with proteins, particularly histones, to form chromatin. This packing allows long DNA molecules to fit inside the cell and regulates gene accessibility. Key structural features include the centromere, which is the constricted region essential for proper segregation during cell division; and telomeres, which cap the ends of linear hromosomas to protect them from degradation.

Hromosomas are typically categorized as autosomes or sex chromosomes. Most diploid organisms carry matching pairs of autosomes and a pair of sex chromosomes, though the number and type of chromosomes vary across species. In humans, somatic cells contain 46 hromosomas (23 pairs), while gametes contain 23 haploid hromosomas. During cell division, hromosomas are replicated in the S phase and then equally segregated through mitosis or meiosis to produce daughter cells.

Variation in hromosome number and structure can influence development and health. Abnormalities such as aneuploidy (an abnormal number of hromosomas), deletions, duplications, or translocations can lead to developmental disorders or cancer. Hromosomas are studied through cytogenetics, including karyotyping and fluorescence in situ hybridization, as well as modern sequencing methods.