How is the DNA template read during transcription?

During transcription, the DNA template is read in the 3' to 5' direction by the RNA polymerase enzyme.

Transcription is a fundamental process in biology where the information in a DNA sequence is copied into a complementary RNA sequence. This process is carried out by an enzyme known as RNA polymerase. The DNA template is read in the 3' to 5' direction, which means that the RNA polymerase moves along the DNA strand from the third carbon atom to the fifth carbon atom in the sugar ring of the nucleotide.

The process begins with the binding of RNA polymerase to a specific sequence on the DNA known as the promoter. This signals the start of a gene, which is a segment of DNA that codes for a specific protein. The RNA polymerase then unwinds the DNA double helix, exposing the nucleotides on each DNA strand.

The RNA polymerase then begins to synthesise a new strand of RNA, using the DNA strand as a template. It matches the DNA nucleotides with complementary RNA nucleotides - adenine (A) with uracil (U), and cytosine (C) with guanine (G). This process continues until the RNA polymerase reaches a sequence on the DNA known as the terminator, which signals the end of the gene.

The newly synthesised RNA strand, which is a mirror image of the DNA strand (except for the replacement of thymine with uracil), then detaches from the DNA template. This RNA strand can then be processed further to become messenger RNA (mRNA), which carries the genetic information from the DNA to the ribosomes, where it is used to synthesise proteins.

In summary, the DNA template is read in the 3' to 5' direction during transcription. This process is carried out by the RNA polymerase enzyme, which synthesises a complementary RNA strand based on the DNA template. This RNA strand can then be used to produce proteins, which are essential for the functioning of the cell.