Small subunit

Definition

The small subunit is a component of the ribosome that binds to mRNA and initiates translation. It plays a crucial role in decoding the mRNA sequence into a polypeptide chain.

5 Must Know Facts For Your Next Test

1. The small subunit of the ribosome binds to the mRNA at the start codon (AUG).
2. It is responsible for the correct positioning of the mRNA and tRNAs during translation.
3. In prokaryotes, the small subunit is 30S, while in eukaryotes, it is 40S.
4. The small subunit works with initiation factors to form the initiation complex.
5. The accuracy of translation initiation largely depends on the proper functioning of the small subunit.

Review Questions

• What role does the small subunit play in protein synthesis?
• How does the size of the small subunit differ between prokaryotes and eukaryotes?
• Why is accurate functioning of the small subunit critical for translation?

Related terms

Large Subunit: The larger component of a ribosome that catalyzes peptide bond formation.

mRNA:

Messenger RNA that carries genetic information from DNA to ribosomes for protein synthesis.

tRNA:

Transfer RNA that brings amino acids to ribosomes during protein synthesis.