Final answer:
Chromatin structure is modified through chromatin remodeling to open or close the chromosomal region required for transcription. Transcription involves the steps of initiation, elongation, and termination, where RNA polymerase binds to the promoter and adds nucleotides to the mRNA strand.
Step-by-step explanation:
Chromatin structure can be modified through a process called chromatin remodeling, which alters the chromosomal structure to open or close it as needed for transcription. When a gene is to be transcribed, the histone proteins and DNA in the chromosomal region encoding that gene are modified to open the promoter region, allowing RNA polymerase and transcription factors to bind and initiate transcription. On the other hand, if a gene is to remain turned off, the histone proteins and DNA have different modifications that signal a closed chromosomal configuration, preventing transcription. The steps involved in transcription are initiation, elongation, and termination, where RNA polymerase binds to the promoter region, adds nucleotides to the mRNA strand, and detaches from the DNA, respectively.