Which of the following statements is correct regarding RNA?
a. Messenger RNA, transfer RNA, and ribosomal RNA play a role in protein synthesis.
b. rRNA is always attached to the rough ER.
c. If the base sequence of DNA is ATTGCA, the messenger RNA template will be UCCAGU.
d. There is exactly one specific type of mRNA for each amino acid.
The Correct Answer and Explanation is :
The correct statement is a. Messenger RNA, transfer RNA, and ribosomal RNA play a role in protein synthesis.
Explanation
1. RNA Types and Their Roles:
RNA (ribonucleic acid) is essential for protein synthesis and exists in three main forms: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA).
- Messenger RNA (mRNA) is synthesized from DNA during transcription and carries the genetic information from the nucleus to the ribosomes, where proteins are made. It serves as a template for the sequence of amino acids in a protein.
- Transfer RNA (tRNA) brings amino acids to the ribosome during translation. Each tRNA molecule has an anticodon that pairs with the corresponding codon on the mRNA, ensuring the correct amino acid is added to the growing polypeptide chain.
- Ribosomal RNA (rRNA) is a component of ribosomes, the cellular structures where protein synthesis occurs. rRNA helps catalyze the formation of peptide bonds between amino acids, facilitating the assembly of proteins.
2. Incorrect Options:
- b. rRNA is always attached to the rough ER. This statement is misleading. While ribosomes (which contain rRNA) are found on the rough endoplasmic reticulum (ER) and are involved in protein synthesis, rRNA itself is not permanently “attached” to the rough ER. Ribosomes can also exist freely in the cytoplasm.
- c. If the base sequence of DNA is ATTGCA, the messenger RNA template will be UCCAGU. This statement is incorrect. The mRNA sequence synthesized from the DNA sequence ATTGCA would be UAACGU. The transcription process involves complementary base pairing (A-U, T-A, C-G, and G-C).
- d. There is exactly one specific type of mRNA for each amino acid. This is not true. Multiple mRNA sequences can code for the same amino acid due to the redundancy of the genetic code (often referred to as codon degeneracy).
In summary, statement a correctly reflects the collaborative roles of mRNA, tRNA, and rRNA in protein synthesis, highlighting their vital functions in translating genetic information into functional proteins.