What is transcription in biology?
Transcription is the process of copying a segment of DNA into RNA. A DNA sequence is read by an RNA polymerase which produces a complementary RNA strand called a primary transcript.
Questions about Transcription (biology)
Short answers, pulled from the story.
When was RNA synthesis by RNA polymerase established in vitro?
Several laboratories established that RNA synthesis by RNA polymerase occurred in vitro in 1965. This discovery revealed an additional factor needed to terminate transcription correctly.
How does RNA polymerase synthesize RNA during transcription?
RNA polymerase reads the antisense strand of DNA from the 3' end to the 5' end and creates a complementary RNA moving from 5' to 3'. The enzyme can only add nucleotides to the 3' end of the growing mRNA chain.
Where are active transcription units located within the nucleus?
Active transcription units cluster in the nucleus at discrete sites called transcription factories. There are approximately 10,000 factories in the nucleoplasm of a HeLa cell.
Why do cancer cells activate telomerase?
Activation of telomerase allows cancer cells to become immortal because every time a linear chromosome is duplicated it shortens. The immortalizing factor of cancer via telomere lengthening due to telomerase occurs in 90% of all carcinogenic tumors.