key term - 60S ribosomal subunit

Definition

The 60S ribosomal subunit is a large component of the eukaryotic ribosome, which plays a crucial role in protein synthesis. It is part of the complete ribosome, which is a complex machinery that translates messenger RNA (mRNA) into polypeptides. The 60S subunit works in conjunction with the smaller 40S subunit to ensure the correct assembly and function of the ribosome during translation, which is an essential process in gene expression and regulation.

5 Must Know Facts For Your Next Test

1. The 60S ribosomal subunit contains three ribosomal RNA molecules and over 40 different proteins, contributing to its large size and complex structure.
2. This subunit is responsible for catalyzing peptide bond formation during protein synthesis, linking amino acids together as per the sequence dictated by mRNA.
3. In eukaryotic cells, the 60S subunit is synthesized in the nucleolus and then exported to the cytoplasm, where it combines with the 40S subunit to form functional ribosomes.
4. Various factors can influence the assembly and function of the 60S ribosomal subunit, including post-translational modifications of its proteins and RNA components.
5. Mutations or malfunctions in the components of the 60S ribosomal subunit can lead to diseases such as cancer or genetic disorders due to improper protein synthesis.

Review Questions

• How does the 60S ribosomal subunit contribute to the process of translation in eukaryotic cells?
  • The 60S ribosomal subunit plays a key role in translation by facilitating the formation of peptide bonds between amino acids, thus synthesizing polypeptides. It pairs with the 40S ribosomal subunit to form a complete ribosome that correctly interprets mRNA sequences. This interaction ensures that the correct amino acids are added in the proper order, ultimately leading to functional protein products.
• What factors influence the assembly and functionality of the 60S ribosomal subunit during protein synthesis?
  • Several factors influence both assembly and functionality, including post-translational modifications of its associated proteins and rRNA components. Additionally, specific translation initiation factors and environmental conditions such as nutrient availability can impact how effectively the 60S subunit assembles with the 40S subunit. Proper assembly is crucial for ensuring accurate translation and gene regulation.
• Evaluate how disruptions in the function of the 60S ribosomal subunit can lead to disease conditions.
  • Disruptions in the function of the 60S ribosomal subunit can have significant consequences on protein synthesis, leading to various disease states. For instance, mutations in rRNA or associated proteins can cause defects in peptide bond formation, resulting in incomplete or malfunctioning proteins. Such issues are linked to diseases like cancer, where aberrant protein synthesis may drive uncontrolled cell growth, and genetic disorders that arise from errors in translating specific genes into functional proteins.

Related terms

40S ribosomal subunit:

The smaller component of the eukaryotic ribosome that pairs with the 60S subunit to form the complete ribosome for protein synthesis.

Polypeptide:

A chain of amino acids linked by peptide bonds that forms a protein after translation is completed.

Translation initiation: The first phase of protein synthesis where the ribosome assembles around the target mRNA, positioning the first tRNA at the start codon.