The Lady in the Lab

Gene expression  is  the molecular process by which DNA  is converted into a functional product called proteins[1]. The two key steps in the production of proteins is Transcription (DNA to RNA) and Translation (RNA to proteins)[1][2]. The processes are different in prokaryotes and eukaryotes. EUKARYOTIC GENE EXPRESSION Unlike prokaryotes, eukaryotic cells have nucleus. This means that transcription and translation cannot occur at the same time. Transcription is carried out inside the nucleus of the cell. Transcription a) Initiation The initiation of transcription in eukaryotes requires the participation of the promoter region, transcription factors, and RNA polymerase. There are several core promoter elements in eukaryotes. The most commonly studied is the TATA box . This is located 25-30 base pairs upstream from the transcription start site. The TATA box is where the transcription factors bind. Transcription factors are composed of several proteins...

Gene expression is  the molecular process by which DNA  is converted into a functional product called proteins[1]. The two key steps in the production of proteins is Transcription (DNA to RNA) and Translation (RNA to proteins)[1][2]. The processes are different in prokaryotes and eukaryotes. PROKARYOTIC GENE EXPRESSION Transcription a) Initiation In prokaryotes, like bacteria, the chromosome is a covalently-closed circle. For transcription to occur, the DNA double helix must partially unwind. The unwound region is called the transcription bubble . A holoenzyme (a fully functioning enzyme) and promoter is necessary for the initiation of transcription[3]. Prokaryotic RNA polymerase  is the holoenzyme which assembles each time a gene is transcribed, and disassembles once transcription is complete. It is composed of 5 polypeptide subunits. These subunits are α, α, β, β', and σ[3]. α-subunits are used to assemble the polymerase on the DNA ...