Which of the following molecules are produced during transcription? (3 points)
Messenger RNA
Ribozymes
Ribosomal proteins
I only
I and II only
II only
I, II, and III
The Correct Answer and Explanation is:
The correct answer is: I only (Messenger RNA).
Explanation:
Transcription is the process in which a segment of DNA is copied into RNA, which will then undergo further processing and translation to produce proteins. During transcription, the DNA sequence is used as a template to synthesize RNA. However, only certain types of molecules are directly produced during this process:
- Messenger RNA (mRNA):
mRNA is the primary product of transcription. It is synthesized from the DNA template strand and carries the genetic information necessary for protein synthesis. The RNA polymerase enzyme is responsible for reading the DNA and synthesizing a complementary mRNA strand. After transcription, mRNA undergoes processing (such as adding a 5′ cap, splicing out introns, and adding a poly-A tail in eukaryotes) before it exits the nucleus (in eukaryotic cells) and is used in translation to make proteins in the ribosomes. - Ribozymes:
Ribozymes are RNA molecules that have catalytic properties, meaning they can accelerate chemical reactions. While some ribozymes are involved in processes such as RNA splicing (removal of introns from mRNA) or ribosomal activities, they are not directly produced during the transcription of a specific gene. Instead, ribozymes are functional RNA molecules that can be part of the broader cellular machinery or involved in processes that occur after transcription. For example, ribozymes like the self-splicing intron may catalyze reactions during RNA processing, but their creation is not a direct outcome of transcription. - Ribosomal proteins:
Ribosomal proteins are not produced during transcription. These proteins are synthesized through the translation of mRNA, specifically the mRNA that encodes ribosomal proteins. Ribosomal proteins are then imported into the nucleus (in eukaryotes) or remain in the cytoplasm (in prokaryotes) and combine with ribosomal RNA (rRNA) to form ribosomes. Ribosomal proteins are a part of translation, not transcription.
Thus, only messenger RNA (mRNA) is directly produced during the transcription process. Therefore, the correct answer is I only.