What is the End Product of Transcription

The end product of transcription is an RNA molecule. Hence, copying the information of genes in the genome into an RNA occurs during the transcription. The three main types of RNA produced by transcription are mRNA, tRNA, and rRNA. Further, transcription is the first step of protein synthesis. During which, the RNA polymerase transcribes the information in a gene, and thus, producing an RNA molecule. Also, during protein synthesis, the mRNA carries the information of a gene from the nucleus to the cytoplasm. Moreover, the other two main types of RNA facilitate the translation.

Key Areas Covered

1. What is Transcription
      – Definition, Process
2. What is the End Product of Transcription
     – Types of Transcripts

Key Terms: mRNA, RNA Polymerase, rRNA, Transcription, tRNA

What is Transcription

Transcription is the first step of protein synthesis and copying of the information in a gene into an RNA molecule. RNA polymerase is the enzyme that catalyzes the transcription. The three steps of transcription are initiation, elongation, and termination. The binding of RNA polymerase to the promoter regions initiates transcription. It is regulated by transcription factors. During elongation, RNA polymerase adds complementary RNA nucleotides to the sequence of the antisense strand. RNA polymerase escapes from the antisense strand when it meets the terminator sequence. The three types of RNA produced in the transcription are mRNA, tRNA, and rRNA. Some other types of non-coding RNA are also produced by transcription. Transcription is shown in figure 1.

Figure 1: Transcription

What is the End Product of Transcription

The end product of transcription is RNA, a single-stranded molecule made up of RNA nucleotides. The three main types of RNA produced in the transcription are mRNA, tRNA, and rRNA.

Messenger RNA

mRNA is responsible for carrying genetic information from the nucleus to the cytoplasm. mRNA is produced by the transcription of protein-coding genes. A process called translation converts the codon sequence of the mRNA into an amino acid sequence of functional proteins.

Transfer RNA

tRNA is responsible for carrying the corresponding amino acid to the ribosomes during translation. Due to the complementary regions, tRNA forms a hairpin loop structure. It carries amino acids by recognizing the codon by their anticodon region. The anticodon region of a tRNA is shown in red in figure 2.

Figure 2: tRNA

Ribosomal RNA

 rRNA is a component of a ribosome which facilitates translation. A ribosome consists of two subunits: small subunit and a large subunit. 

Conclusion

The end product of transcription can be either mRNA, tRNA, rRNA or other non-coding RNA. The three main types of RNA have a role in the synthesis of amino acid chains. mRNA is the transcript that contains the codon sequence for the synthesis of a polypeptide chain. tRNA brings corresponding amino acids to the translation complex. rRNA forms ribosomes in which translation takes place.

Reference:

1. “Overview of Transcription.” Khan Academy, Available here.

Image Courtesy:

1. “DNA transcription” By reworked and vectorized by myself – National Human Genome Research Institute,  (Public Domain) via Commons Wikimedia
2. “TRNA-Met yeast” By Yikrazuul – Own work; PMID 19925799 (CC BY-SA 3.0) via Commons Wikimedia