DNA (De-oxyribonucleic acid)

DNA (De-oxyribonucleic acid)
The DNA can be found at two sites in a cell, in large amount in nucleus as a part of chromosomes and a very small amount in cytoplasm as a part of mitochondria. Both these forms of DNA differ from each other in certain details, like the DNA thread is in the form of ring. The nitrogenous bases differ and they are mainly of maternal in origin. In mitochondrial DNA while the chromosomal DNA is in the form of double helix with complementary strands running in opposite direction for quick Fidel application. There is 10 nucleotide pair per complete turn of the double chain.
The replication is making a copy of DNA. This takes place during ‘S’ phase of interphase taking about 7 hours before the onset of mitosis or meiosis. Thus during replication
· Two strands of DNA helix separates out.
· Each strand act as a template.
· Each template forms complementary strand.
· One template with its complementary strand forms anew DNA molecule.