Question

Write a paragraph describing the abbreviated chemical reactions that summarize RNA polymerase-directed transcription.

Short answer

Question: Briefly describe the major steps and chemical reactions involved in RNA polymerase-directed transcription. Answer: The RNA polymerase-directed transcription process consists of three major steps: Initiation, Elongation, and Termination. In Initiation, RNA Polymerase binds to the DNA promoter, leading to the reaction: RNA Polymerase + DNA_promoter -> RNA Polymerase-DNA_complex. During Elongation, RNA Polymerase adds complementary RNA nucleotides to the DNA template, represented by the reaction: RNA Polymerase-DNA_complex + NTP -> RNA Polymerase-DNA_complex + RNA_n+1. Termination occurs when RNA Polymerase encounters a termination signal, resulting in the reaction: RNA Polymerase-DNA_complex + Termination_Signal -> RNA Polymerase + DNA + RNA_molecule. This process allows for the synthesis of RNA molecules from a DNA template, enabling gene expression and protein synthesis.

Step-by-step solution

Initiation

In the initiation step, the RNA polymerase enzyme binds to a specific region on the DNA called the promoter. The enzyme then unwinds the two strands of the DNA molecule to expose the template strand that will be used for RNA synthesis. The abbreviated chemical reaction for this step can be written as: RNA Polymerase + DNA_promoter -> RNA Polymerase-DNA_complex

Elongation

During the elongation step, the RNA polymerase enzyme moves along the DNA template strand and adds complementary RNA nucleotides by forming phosphodiester bonds. This process continues until the entire RNA molecule is synthesized. The abbreviated chemical reaction for this step can be written as: RNA Polymerase-DNA_complex + NTP (Nucleotide) -> RNA Polymerase-DNA_complex + RNA_n+1 (where n represents the length of the RNA chain)

Termination

Finally, in the termination step, the RNA Polymerase reaches a specific termination sequence on the DNA which causes the enzyme to release the newly synthesized RNA molecule and the DNA template. This allows the DNA molecule to rewind and return to its original double helix structure while the RNA molecule is now free for further processing or translation. The abbreviated chemical reaction for this step can be written as: RNA Polymerase-DNA_complex + Termination_Signal -> RNA Polymerase + DNA + RNA_molecule In summary, the RNA polymerase-directed transcription process can be described through a series of abbreviated chemical reactions that involve the initiation, elongation, and termination steps. This process allows for the synthesis of RNA molecules from a DNA template, which is a key step in gene expression and protein synthesis.