Translation Machinery Components

Study Notes

Translation Machinery Components

Translation is the final step of gene expression, accounting for 25% of the cell's weight in molecules related to gene expression.
A cell produces approximately 3,500 proteins from one mRNA, making protein synthesis a costly process for the cell, much more so than transcription.
76% of the cell's energy expenditure is dedicated to translation during growth.
In yeast, 60% of transcription is RNA pol I, 10% is RNA pol III, and over 20% of RNA pol II is dedicated to ribosomal proteins, making up >75% of transcription focused on translation machinery.

Origin of Translation Machinery

The RNA world, lacking ribosomes and proteins, saw the emergence of the genetic code and the first proteins organized according to RNA sequence.
Initial translations occurred spontaneously, generating the first proteins that gave rise to ribosomes.
tRNA is thought to be the first element of the translation machinery to appear, being purely RNA-based.
The peptidyl-transferase activity is present in rRNA and can occur in the absence of enzymes, although it's not favorable.
This suggests that once tRNAs are charged, they recognize messenger codons, facilitating the transpeptidation reaction.
The autogenous protoribosome emerged later, with the insertion of proteins that aid stabilization.
Aminoacyl-tRNA synthetases (AaRS) are more recent, having appeared twice, and are still evolving.

Description

Learn about the components of translation machinery, the final step of gene expression. Discover the energy cost and protein production process in cells. Test your knowledge of cellular biology and gene expression!