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A chromatid (Greek khrÅmat- 'color' + -id) is one half of a duplicated chromosome. Before replication, one chromosome is composed of one DNA molecule. In replication, the DNA molecule is copied, and the two molecules are known as chromatids. [1] During the later stages of cell division these chromatids separate longitudinally to become ...
A chromosome is a package of DNA with part or all of the genetic material of an organism. In most chromosomes, the very long thin DNA fibers are coated with nucleosome -forming packaging proteins; in eukaryotic cells the most important of these proteins are the histones. These proteins, aided by chaperone proteins, bind to and condense the DNA ...
Following chromosomal DNA replication, the blue chromosome is composed of two identical sister chromatids and the pink chromosome is composed of two identical sister chromatids. In mitosis, the sister chromatids separate into the daughter cells, but are now referred to as chromosomes (rather than chromatids) much in the way that one child is ...
Overview. [edit] Chromosomes are linear arrangements of condensed deoxyribonucleic acid (DNA) and histone proteins, which form a complex called chromatin. [ 2 ] Homologous chromosomes are made up of chromosome pairs of approximately the same length, centromere position, and staining pattern, for genes with the same corresponding loci.
The ensuing S phase starts when DNA synthesis commences; when it is complete, all of the chromosomes have been replicated, i.e., each chromosome consists of two sister chromatids. Thus, during this phase, the amount of DNA in the cell has doubled, though the ploidy and number of chromosomes are unchanged.
When cells enter mitosis, the sister chromatids (the two copies of each chromosomal DNA molecule resulting from DNA replication in chromatin form) are linked along their length by the action of the cohesin complex. It is now believed that this complex is mostly released from chromosome arms during prophase, so that by the time the chromosomes ...
mitosis. produces two genetically identical cells, each with the same number of chromosomes as in the parent. Meiosis begins with a diploid cell, which contains two copies of each chromosome, termed homologs. First, the cell undergoes DNA replication, so each homolog now consists of two identical sister chromatids.
Chromatin. The major structures in DNA compaction: DNA, the nucleosome, the 11 nm beads on a string chromatin fibre and the metaphase chromosome. Chromatin is a complex of DNA and protein found in eukaryotic cells. [ 1 ] The primary function is to package long DNA molecules into more compact, denser structures.