DNA transcription takes place in the nucleus of a cell, which is where DNA is located. The process begins when the enzyme RNA polymerase hooks itself to a specific sequence found on the DNA at a place called the promoter region.
The purpose of DNA transcription is to copy genetic information from DNA to RNA so that the information in RNA can be used to produce proteins. This process helps preserve the integrity of the DNA information and prevents it from becoming tainted.
One of the main differences in DNA and RNA is the composition of their nucleotide bases. DNA contains adenine, guanine, cytosine and thymine. RNA also contains adenine, guanine and cytosine, but its fourth base is uracil.