Where Does Transcription Occur

Living beings are made up of cells. These cells conduct many functions which help in sustaining a healthy and normal life. One of the most important functions of the cell is protein synthesis. This is done with the help of hereditary material, DNA and RNA. Both are made up of nucleic acids and play an important role in transferring genetic information from one generation to the other. The protein synthesis process can be divided into two important processes: transcription and translation. Both of these process are done inside the cell but they take place at different places. In this article we are going to discuss where exactly the transcription occur in the cell and what is the process.

Where Does Transcription Occur in a Eukaryotic Cell

Transcription is a process in which the DNA is transcribed into mRNA. This is a very important part of the protein synthesis process. Well, as we know eukaryotic cells are facilitated with the nucleus. They can have one or more nucleus. This nucleus contains the genetic materials such as DNA and RNA. These materials actively participate in the process of protein synthesis. The DNA transcription takes place inside the nucleus. In the process mRNA is formed. Then the transcribed mRNA comes out of the nucleus pore into the cytoplasm. The translation process takes place and thus completes the process of protein synthesis.

The process of transcription is initiated when the DNA molecule uncoils its strands by breaking the hydrogen bonds which hold the complementary base pairs together. When the strand uncoils, one of its parts behaves as a template for the production of mRNA and is known as anti-sense strand. The other left over part is the sense strand. Then RNA polymerase enzyme which has the sigma factor recognizes the DNA template. The complementary ribonucleotides are attracted towards the template and arrange themselves opposite to the DNA template and to their specific site. Only thymine is replaced by uracil in the RNA molecule (the only difference in the RNA and DNA coding). Once the molecule is completed, it detaches itself from the DNA and the rest of the DNA strands attach again with the help of hydrogen bond. The newly formed RNA molecules contain messages for protein synthesis hence it is known as mRNA or messenger RNA molecule. This molecule then goes out of the nuclear membrane and then the rest of the process of protein synthesis which consists of DNA translation, is completed.

Where Does Transcription Occur in a Prokaryotic Cell

Prokaryotic cells are the primitive cells which lack a nucleus. This is the reason why the entire process of protein synthesis in the prokaryotic cell takes place in the cytoplasm. The transcription and the translation is done alongside simultaneously. The process is nearly the same as in eukaryotes, but the only difference is the place where it takes place. The eukaryotes have a membrane bound nucleus. Hence the ribosomes do not reach the mRNA to carry on the translation process. But in the prokaryotes the ribosome is easily available in the cytoplasm and hence both the entire processes of protein synthesis takes place simultaneously.

Transcription process in prokaryotes can be divided into three stages, initiation, elongation and termination. In the initiation, the RNA polymerase binds to the sigma factor to form holoenzyme. This enzyme recognizes the promoter region in the DNA to form a closed complex. The RNA then starts the transcription and proceeds towards the elongation stage. In the elongation process the RNA transcript increases in length. Then finally in the termination stage the RNA polymerase pauses and the mRNA molecule is terminated from the DNA molecule.

So here we come to an end of this article. I hope by now you know where exactly does transcription occur in different cells and what is its basic process. Protein synthesis is an important function of the cell and hence an important part of DNA research and studies.