What is recognized by an aminoacyl tRNA synthetase?
An aminoacyl-tRNA synthetase (aaRS or ARS), also called tRNA-ligase, is an enzyme that attaches the appropriate amino acid onto its corresponding tRNA. It does so by catalyzing the transesterification of a specific cognate amino acid or its precursor to one of all its compatible cognate tRNAs to form an aminoacyl-tRNA.
What is a significant difference between translation in bacterial cells and eukaryotic cells?
In a eukaryotic cell, transcription occurs in the nucleus, and translation occurs in the cytoplasm. In a prokaryotic cell, transcription and translation are coupled; that is, translation begins while the mRNA is still being synthesized.
Why does attenuation not occur eukaryotes?
1). There is no coupling of transcription and translation in eukaryotic cells as in bacterial cells. Consequently, ribosome movement and arrest cannot modulate attenuation.
How is translation terminated in prokaryotes?
Termination of translation occurs when a nonsense codon (UAA, UAG, or UGA) is encountered. Upon aligning with the A site, these nonsense codons are recognized by protein release factors that resemble tRNAs.
How does a bacterial ribosome initially bind to the mRNA?
How does a bacterial ribosome initially bind to the mRNA? An aminoacyl-tRNA synthetase has a mutation such that it binds the tRNA with the anticodon 3′ GCA 5′ and attaches the amino acid glycine to its 3′ end.
How does ribosome recognize mRNA?
This base-pairing interaction enables bacterial ribosomes to initiate translation not only at the 5´ end of an mRNA but also at the internal initiation sites of polycistronic messages. In contrast, ribosomes recognize most eukaryotic mRNAs by binding to the 7-methylguanosine cap at their 5´ terminus (see Figure 6.39).
Where a charged tRNA is bound?
There are three distinct sites in a ribosome: the A site (aminoacyl-tRNA), where the incoming charged tRNA enters; the P site (peptidyl-tRNA), where the tRNA with the growing peptide chain resides; and the E site, where the tRNA (devoid of its amino acid) exits.
Which mRNA codons end the process of translation?
Translation ends in a process called termination. Termination happens when a stop codon in the mRNA (UAA, UAG, or UGA) enters the A site. Stop codons are recognized by proteins called release factors, which fit neatly into the P site (though they aren’t tRNAs).
What is a Anticodon?
An anticodon is a trinucleotide sequence complementary to that of a corresponding codon in a messenger RNA (mRNA) sequence. An anticodon is found at one end of a transfer RNA (tRNA) molecule.
When mRNA leaves the nucleus where does it go?
The molecule of mRNA then leaves the nucleus and goes to a ribosome in the cytoplasm, where translation occurs. During translation, the genetic code in mRNA is read and used to make a protein. These two processes are summed up by the central dogma of molecular biology: DNA → RNA → Protein.