What does RNA do during protein synthesis - …
9. As the ribosome moves by two codons, next round of protein synthesis is initiated by the attachment of a new ribosome. Thus, at a time, a single mRNA is found to be attached with many ribosomes with their polypeptides of different length, (shortest polypeptide at the 5′ end of the mRNA and longest at the 3′ end), called polysomes.
Fig. 8.15 Peptide bond formation in growing polypeptide.
10. Ultimately, the A-site of ribosome is occupied by the termination codon (UAA,UAG or UGA) at the 3′ end of mRNA, which is not recognized by any tRNA. Thus, the termination of the protein synthesis is helped by the release factors RFl, RF2 and RF3 (in eukaryotes eRF1), which release the newly synthesized polypeptide chain from the P-site (Fig. 8.16).
Translation: Making Protein Synthesis Possible
The process of synthesis of proteins from mRNA (translation of language of nucleic acids into the language of proteins) is called translation. There are 20 different types of amino acids, which constitute various proteins, and these amino acids themselves cannot recognize their respective codons in the mRNA. Different amino acids are carried by their specific tRNA molecules at the
site of protein synthesis (mRNA). There are about 55 types of tRNA molecules available in the cytoplasm, so that one amino acid may have more than one tRNAs.
that are present in mRNA and contain the information of proteins are known as exons. Thus, HnRNA produced after transcription is quite longer than the mRNA. Most of the extra nucleotide sequences, including introns, are cleaved by snurp. Moreover, after removal of the extra nucleotides from the 3′ end of the HnRNA, poly A tail is added that is required for the stability of the mRNA. Similarly, after removal of extra nucleotides from the 5′ end, a cap of 7-methyl guanosine (7mG) is added that is required for the translation process. The production and processing of HnRNA occurs in the nucleus from where it escapes into the cytoplasm through nuclear pores for the translation process (Fig 8.11 and 8.12).
Protein synthesis :: DNA from the Beginning
Now two things happen. The transfer RNA carrying a methionine attaches itself to the AUG codon by pairing its anti-codon bases with the complementary bases on the messenger RNA. And the second, bigger part of the ribosome attaches to the system as well.
RNA acts as the information bridge between DNA and protein
The process of synthesis of RNAs (mRNA, tRNA and rRNA) from DNA by the enzyme RNA polymerase is known as transcription. At the time of transcription, the RNA polymerase binds with double stranded DNA (gene) at a particular site (in prokaryotes known as promoter site) and after unwinding of the two strands of DNA by the rotation of the DNA, it starts copying one of
the two strands, known as coding strand (sense strand or template strand). The other strand of the DNA, which is not copied for the RNA synthesis, is known as non-coding strand (antisense strand) (Fig. 8.6).
This lesson discusses the vital role mRNA plays in protein synthesis
In the diagram, the anti-codon is for the amino acid methionine. The messenger RNA code for methionine is AUG. If you look at the code in the anti-codon for methionine, it is UAC. That is exactly complementary to AUG. The U in the anti-codon will pair with the A in the messenger RNA; the A in the anti-codon pairs with the U in the mRNA; and the C in the anti-codon pairs with the G in the mRNA.
Protein biosynthesis - Wikipedia
At the 3' end of every transfer RNA molecule, the chain ends with the sequence of bases C C A. Remember that the bases in RNA and DNA are attached to a backbone of alternating phosphate and sugar groups. At the very end of the chain is the -OH group on the 3' carbon of a ribose ring.
Protein synthesis is the process ..
Transfer RNA is a short bit of RNA containing about 80 or so bases. These are mostly the same bases as in messenger RNA (A, U, G and C), but it also contains some modified bases which won't concern us at this level. A model of a typical transfer RNA looks like this: