AP BIOLOGY

Detailed explanation-1: -DNA replication, transcription, and RNA processing all take place within the nucleus, with only the final stage of gene expression (translation) localized to the cytoplasm.

Detailed explanation-2: -Transcription occurs in the nucleus whereas the major mRNA decay pathways operate in the cytoplasm. As synthesis and decay processes contribute equally to maintaining mRNA levels, it is quite likely that organisms have evolved a mechanism to coordinate events in the two compartments.

Detailed explanation-3: -In transcription, DNA is converted to mRNA. It takes place in the nucleus of a cell. The newly formed mRNA, undergoes processing, and moves out into the cytoplasm through the nuclear pores, to proceed with the next step of protein synthesis, which is translation.

Detailed explanation-4: -Transcription is the process in which a gene’s DNA sequence is copied (transcribed) to make an RNA molecule. RNA polymerase is the main transcription enzyme. Transcription begins when RNA polymerase binds to a promoter sequence near the beginning of a gene (directly or through helper proteins).

Detailed explanation-5: -Transcription occurs in the nucleus and not in the cytoplasm in eukaryotes because eukaryotes store the DNA in the nucleus. In prokaryotes, there is no nucleus and the DNA is in the cytoplasm. Thus, transcription can occur in the cytoplasm as well.