Which component is directly involved in translation?
(A) RNA polymerase
(C) spliceosome
(B) ribosome
(D) DNA
The Correct Answer and Explanation is:
The correct answer is (B) ribosome.
Explanation:
Translation is the process in which a cell decodes messenger RNA (mRNA) into a sequence of amino acids, which then fold to form proteins. This occurs in the cytoplasm and is carried out by the ribosome. The ribosome serves as the site where the mRNA is “read” and translated into a corresponding amino acid sequence, forming a polypeptide chain that will eventually fold into a functional protein.
Here’s a breakdown of the translation process:
- Initiation: The process begins when the mRNA, which carries the genetic information from DNA, binds to the ribosome. The ribosome consists of two subunits—large and small—which assemble around the mRNA to start the translation. The small subunit binds to the mRNA’s start codon (usually AUG), and the large subunit attaches to form the full ribosome.
- Elongation: During this phase, transfer RNA (tRNA) molecules, each carrying a specific amino acid, bind to the mRNA’s codons through complementary anticodons. The ribosome moves along the mRNA strand, reading each codon and facilitating the bonding of amino acids into a growing polypeptide chain. The ribosome moves in a 5′ to 3′ direction along the mRNA, assembling the amino acids in the correct order as dictated by the mRNA sequence.
- Termination: When the ribosome encounters a stop codon (e.g., UAA, UAG, UGA) on the mRNA, translation ends. The newly formed polypeptide is released, and the ribosome dissociates from the mRNA.
Other components listed, like RNA polymerase, spliceosome, and DNA, are involved in different stages of gene expression:
- RNA polymerase is essential for transcription, not translation. It synthesizes mRNA from a DNA template.
- The spliceosome is involved in RNA splicing, which processes the mRNA before translation.
- DNA provides the template for transcription but does not directly participate in translation.
Thus, the ribosome is the central component directly involved in the process of translation.