Question

Explain how the genetic code is used to make protein.

Answer 1

- Genetic code are present on the mRNA . they are triplet contains three nucleotide sequences.

- once transcription is over the genetic information from DNA are transcribed to the mRNA as codons.

- so mRNA leaves the nucleus and come to the cytoplasm.

- In the cytoplasm translation occurs. Translation refers to the process of polymerisation of amino acid to form polypeptide.

- The cellular factor responsible for synthesizing proteins is the ribosome. The ribosome consists of structural RNAs and and about 80 different proteins.  

- In it's inactive state it exists as two subunits ; a smaller subunit and a larger subunit.

- When the small subunit encounter a mRNA , the process of translation of mRNA into proteins begins.there are two sites in the large subunit for subsequent amino acid to bind to and thus be close enough to each other for formation of peptide bond.

- A translational unit in mRNA is the sequence of RNA that is flanked by the start codon and the stop codon and codes for a polypeptide.

- For initiation ribosome bind to the start codon (AUG) that is only recognised by the initiator tRNA.

-The ribosome proceed to the elongation phase of the protein synthesis . During this stage , complexes composed of amino acid linked to an tRNA , subsequently bind to the appropriate codon in the mRNA by forming complementary base pair with the tRNA anticodon.

-The ribosome moves from codon to codon along the mRNA . Amino acids are added one by one , translated into polypeptide sequences dictated by DNA and represented by mRNA .

-. At the end release factors bind to the stop codon and terminating the translation and releasing the complete polypeptide from the ribosome.

- This is how Genetic code is used to make proteins.

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