Advanced Dental Admission (ADAT) Practice Test

Transcription occurs in the nucleus of eukaryotic cells, where the DNA is located. During transcription, a specific segment of DNA is copied into mRNA by the enzyme RNA polymerase. This process is essential because it allows the genetic information stored in DNA to be converted into a format that can be translated into proteins.

The nucleus serves as the site of transcription because it houses the genetic material and provides the necessary environment for RNA polymerase and other transcription factors to perform their roles. Once the mRNA is synthesized, it then undergoes several modifications, such as splicing and the addition of a 5' cap and poly-A tail, before being exported from the nucleus to the cytoplasm, where translation occurs.

Transcription does not take place in the cytoplasm, nucleolus, or ribosomes. The nucleolus is involved in the synthesis of ribosomal RNA (rRNA) and assembly of ribosomes, while ribosomes are the cellular machinery where translation occurs, not transcription. Hence, the nucleus is the correct location where the transcription process occurs.