describe process rna polymerase
RNA polymerase is an enzyme that carries out the transcription process, in which DNA is used as a template to produce RNA. The process of RNA polymerase can be described as follows:
1. Activation: RNA polymerase binds to the DNA molecule at the promoter region, which is located at the start of the gene sequence.
2. Initiation: RNA polymerase unwinds the DNA molecule and synthesizes a short RNA sequence of about 10 nucleotides. This sequence is called the "initiation complex."
3. Elongation: RNA polymerase moves down the DNA molecule, synthesizing RNA strands as it goes. It reads the DNA sequence and adds complementary RNA nucleotides to the new RNA strand.
4. Termination: When RNA polymerase reaches the end of the gene sequence, it stops transcription and releases the newly formed RNA molecule.
Throughout the process, RNA polymerase moves down the DNA sequence, reading the gene sequence and synthesizing a complementary RNA strand. The RNA polymerase enzyme is responsible for catalyzing the chemical reactions that join the RNA nucleotides together, forming the RNA strand.
The process of RNA polymerase can be described as follows:
1. Initiation: RNA polymerase binds to the DNA template strand at the promoter region. Promoters are specific nucleotide sequences that signal the beginning of a gene. RNA polymerase unwinds and separates a small portion of the DNA double helix, forming a transcription bubble.
2. Elongation: RNA polymerase adds complementary RNA nucleotides to the growing RNA strand, using the DNA template strand as a guide. RNA nucleotides (A, U, G, and C) are matched with their complementary bases on the DNA template (U pairs with A, A pairs with T, G pairs with C, and C pairs with G). The RNA polymerase moves along the DNA template strand, synthesizing an RNA molecule in the 5' to 3' direction.
3. Termination: When the RNA polymerase reaches the termination sequence, it triggers the detachment of the RNA polymerase from the DNA template strand, causing the newly synthesized RNA molecule to be released. Termination sequences may vary, but they often include specific nucleotide patterns that signal the end of a gene.
4. Post-transcriptional modifications: In some cases, the newly synthesized RNA molecule may undergo additional modifications before it becomes a functional mRNA molecule. These modifications can include the removal of non-coding regions (introns) and the addition of a cap and poly-A tail to stabilize the mRNA molecule and assist in its transport out of the nucleus.
Overall, RNA polymerase plays a crucial role in gene expression by synthesizing RNA molecules from DNA templates. These RNA molecules serve as intermediates that carry the genetic information from the DNA to the ribosomes, where they are then translated into proteins.