Transcription uses which enzyme

The newly formed mRNA copies of the gene then serve as blueprints for protein synthesis during the process of translation. Further Exploration Concept Links for further exploration translation transcription unit gene expression frameshift mutation nonsense mutation RNA DNA enhancer promoter differentiation gene expression transcription factor intron exon chromatin histones mutation helicase transcriptome phosphate backbone poly-A tail nuclear pore primase TATA box hairpin loop mRNA DNA polymerase mRNA chromatin remodeling cis-regulatory element RNA polymerase catabolite repression methylation.

Related Concepts You have authorized LearnCasting of your reading list in Scitable. Do you want to LearnCast this session?

Overview of Transcription. Triplets are groups of three successive nucleotide bases in DNA. Codons are complementary groups of bases in mRNA.

Transcription takes place in three steps: initiation, elongation, and termination. The steps are illustrated in Figure 2. Figure 2. Transcription occurs in the three steps—initiation, elongation, and termination—all shown here. Initiation is the beginning of transcription. Upon the addition of a ribonucleotide, the polymerase II enzyme undergoes translocation to put the next template base in the proper position, with an empty nucleotide binding site at the end of the RNA molecule 3.

The specificity for adding a ribonucleotide rather than a deocxyribonucleotide can be attributed to the recognition of the ribose sugar as well as the hybrid RNA-DNA double helix. Throughout elongation, the transcribed RNA molecule is proofread to ensure no deoxynucleotides or incorrect bases are inserted 3.

After the RNA has elongated through the length of the gene, it reaches termination signals and the transcribed RNA is released. Termination follows elongation and is a crucial step in the transcription process. Many consequences are possible if polymerase II never responds to termination signals.

For example, failure to end elongation can lead to a reduction in the expression of a down stream gene by interfering with the initiation complex of that gene. It could also obstruct the correct transmission of eukaryotic chromosomes. Research on termination mechanisms points to two sequences that are required for proper termination. While both of these sequences make only small contributions, they are both essential in the termination process 5.

Eukaryotic Transcription The process of eukaryotic transcription is separated into three phases, initiation, elongation, and termination. Elongation Once the DNA strand is properly positioned in the metal ion active site of polymerase II, elongation begins.