CBSE Class 9 Answered
Chromatin is the complex of nucleic acids (DNA and RNA) and proteins (primarily histones), in the cell nucleus that stains readily with basic dyes and condenses to form chromosomes during cell division. is found inside the nuclei of eukaryotic cells, and within the nucleoid in prokaryotic cells. It is divided between heterochromatin (condensed) and euchromatin (extended) forms. The functions of chromatin are to package DNA into a smaller volume to fit in the cell, to strengthen the DNA to allow mitosis and meiosis, and to serve as a mechanism to control expression and DNA replication.
Chromatid is either of the two daughter strands of a replicated chromosome that are joined by a single centromere and separate during cell division to become individual chromosomes. The term is used so long as the centromeres remain in contact. When they separate (during anaphase of mitosis and anaphase 2 of meiosis), the strands are called daughter-chromosomes. In other words, a chromatid is 'one-half of a replicated chromosome'.
Chromsome is a threadlike linear strand of DNA and associated proteins in the nucleus of eukaryotic cells that carries the genes and functions in the transmission of hereditary information. Chromosomes can change their conformation and degree of compaction throughout the cell cycle. During interphase, the major portion of the cycle, chromosomes are not visible under the light microscope because, although they are very long, they are extremely thin. However, during cell division, the chromosomes become compacted into shorter and thicker structures that can be seen under the microscope.
(The term chromosome is usually reserved for the structure when it is condensed and readily visible during cell division. At other times the chromosome appears as a fibrous structure, called the chromonema, consisting of accumulations of chromatin, the dye-absorbing material. During nuclear division, when each chromosome splits, each of the duplicate chromosomes is called a chromatid.)