SCIENCE 10 Q3 GENE EXPRESSION

• Gene expression is a process by which information from the gene is used to make mRNA (mRNA), which act as template to construct proteins. It involves the flow of information from the gene to construct protein. It comprises two stages: Transcription (RNA synthesis) and Translation (protein synthesis). Gene expression is a vital process that ensures specific proteins are produced or synthesized at the right time and in the right quantities.

  
• Transcription occurs inside the nucleus of a eukaryotic cell. It is a process of producing or synthesizing mRNA using the DNA template. It involves the transfer of information copied from the DNA. The RNA is called a messenger RNA since it carries the “message’ or genetic information from the DNA to the ribosomes, where the information is used to make proteins.  

   

  
• Initiation- RNA polymerase binds to the promoter site of the DNA molecule. The promoter is a region in the DNA molecule that serves as the starting point of transcription. RNA polymerase unwinds the DNA double helix and opens the DNA molecule that will be transcribed.
• (1) Elongation - As the DNA opens, RNA polymerase moves along DNA template strand, the strand that serve as template for the new RNA strand, and links free RNA nucleotides that pair with the nitrogenous bases of the complementary base strand following the rule: Cytosine ( C ) pairs with Guanine (G) , Adenine (A) pairs with Uracil (U).

  
• • Termination: transcription stops when the RNA polymerase encounters a stop sequence. The RNA polymerase separates from the DNA template. The RNA molecule is release and moves to the cytoplasm.