<unk> is the process by which genetic information from DNA is transferred into RNA. DNA sequence is enzymatically copied by RNA polymerase to produce a complementary nucleotide RNA strand. One significant difference between RNA and DNA sequence is the presence of U, or uracil in RNA instead of the T, or thymine of DNA. In the case of protein-encoding DNA,<unk> is the first step that usually leads to the expression of the genes, by the production of the mRNA intermediate, which is then translated following the genetic code into a functional peptide or protein.
The stretch of DNA that is transcribed into an RNA molecule is called a<unk> unit.  A<unk> unit that is translated into protein contains sequences that direct and regulate protein synthesis in addition to coding the sequence that is translated into protein. The regulatory sequence that is before, or 5', of the coding sequence is called 5' untranslated (5'UTR) sequence, and sequence found following, or 3', of the coding sequence is called 3' untranslated (3'UTR) sequence.<unk> has some proofreading mechanisms, but they are fewer and less effective than the controls for copying DNA; therefore,<unk> has a lower copying fidelity than DNA replication.
As in DNA replication,<unk> proceeds in the 5' → 3' direction. The DNA template strand is read 3' → 5' by RNA polymerase and the new RNA strand is synthesized in the 5'→ 3' direction. RNA polymerase binds to the 3' end of a gene (promoter) on the DNA template strand and travels toward the 5' end. Except for the fact that thymines in DNA are represented as uracils in RNA, the newly synthesized RNA strand will have the same sequence as the coding (non-template) strand of the DNA. For this reason, scientists usually refer to the DNA coding strand that has the same sequence as the resulting RNA when referring to the directionality of genes on DNA, not the template strand.<unk> is divided into 3 stages: initiation, elongation and termination.
Transcription 
Signal transduction
Gene expression
Reverse transcription
Polymerization
Drug metabolism
Fertilization
Reproduction