Which type of RNA carries activated amino acids to the ribosome for assembly into proteins?
A. mRNA
B. sRNA
C. tRNA
D. rRNA
The correct answer and explanation is :
The correct answer is:
C. tRNA (Transfer RNA)
Explanation:
Transfer RNA (tRNA) is a crucial molecule in the process of protein synthesis. Its primary function is to transport activated amino acids to the ribosome, where proteins are assembled. The process occurs in several key steps:
- Amino Acid Activation
Each tRNA molecule is specific to a particular amino acid. An enzyme called aminoacyl-tRNA synthetase catalyzes the attachment of the correct amino acid to its corresponding tRNA. This process requires ATP and results in an “activated” amino acid, forming an aminoacyl-tRNA complex. - tRNA Structure and Function
tRNA has a characteristic cloverleaf structure with three major regions:
- Amino Acid Attachment Site: The 3′ end of the tRNA binds to the specific amino acid.
- Anticodon Loop: Contains a sequence of three nucleotides (anticodon) that base-pairs with the complementary codon on messenger RNA (mRNA).
- D and TψC Loops: Help in proper folding and recognition by ribosomes and enzymes.
- Role in Translation
During protein synthesis, the ribosome facilitates the matching of each tRNA’s anticodon with the codon on mRNA. As the ribosome moves along the mRNA, tRNA molecules sequentially bring amino acids, forming peptide bonds and elongating the polypeptide chain. - Significance
tRNA ensures the correct translation of genetic code into proteins, making it a fundamental component of gene expression. Without tRNA, the accurate transfer of amino acids for protein synthesis would not be possible.
Thus, tRNA (transfer RNA) is responsible for carrying activated amino acids to the ribosome, making option C the correct answer.