CHROMATIN vs CHROMOSONE vs CHROMATID
These three terms are often used synonymously , however , there are some key differences .
● DNA is usually loosely packed as unraveled chromatin within the nucleus of all non-dividing cells . This allows processes such as replication and transcription to occur more easily . This loosened form of chromatin is called euchromatin . Chromatin that is condensed and resembles the material seen in graphics depicting cell division is known as heterochromatin .
● Chromosomes are nothing more than the body ’ s chromatin divided into distinct physical structures . Human chromatin is divided into 23 chromosomes , 22 of which are numbered chromosomes ( autosomes ) and the remaining one being a sex chromosome , either X or Y .
● When DNA is replicated , there are two identical DNA strands . These genetically identical strands are called sister chromatids and have the X-shape that we typically associate with chromosomes .
NOT TO BE CONFUSED !
● A homologous pair of chromosomes : two paired chromosomes which were inherited separately , one from each parent , each the same as the other .
● Sister chromatids : one chromosome and its exact copy replicated during interphase and attached during mitosis .
During interphase , the amount of DNA within the cell precisely doubles . Therefore , after DNA replication but before cell division , each cell contains two copies of each chromosome .