How the protein synthesis occurred?
Answer
Protein synthesis can be divided into two stages which is
transcription and translation.
At transcription, RNA polymerase will attach to promoter. When it moves along
the DNA , Hydrogen bond between the two stands of DNA molecule will break and
the double helix strand are separated.
Only one strand called template strand will be used for transcription.
As RNA polymerase moves along the template strand, complementary ribonucleotides
will pair with the bases of the template strand. The pairing via correct base
pairs A-T , G-C catalysed by RNA polymerase.
Transcription stops when RNA polymerase reaches the termination codon of the
DNA template strand. The nucleotide on template strand then linked to form mRNA
catalysed by RNA polymerase.
the mRNA then detached from the DNA and move into cytoplasm.
In cytoplasm, translation occurs when ribosome come and bind with mRNA to form
amino-tRNA complex . Then it will pair with the initiation codon of mRNA. The
initiator codon is AUG.
amino-tRNA complex pair with mRNA codon next to AUG. Amino acid is transferred
to ribosome linked to 1st amino acid by peptide bond. Ribosome move
from one codon by one codon till 3’ end. At each codon amino acid-tRNA complex
with correct anticodon pair with mRNA codon on ‘A’ site. Amino acid transferred
by tRNA to ribosome is linked to elongation of polypeptide. tRNA on ‘P’ site
detaches and process repeats. The polypeptide synthesis end when ribosome
reaches the terminator codon, UAA.
The first amino acid is cut from polypeptide. One completed polypeptide will
now detached from ribosome and mRNA. Ribosome detached from mRNA and can be
used again.
At transcription, RNA polymerase will attach to promoter. When it moves along the DNA , Hydrogen bond between the two stands of DNA molecule will break and the double helix strand are separated.
Only one strand called template strand will be used for transcription.
As RNA polymerase moves along the template strand, complementary ribonucleotides will pair with the bases of the template strand. The pairing via correct base pairs A-T , G-C catalysed by RNA polymerase.
Transcription stops when RNA polymerase reaches the termination codon of the DNA template strand. The nucleotide on template strand then linked to form mRNA catalysed by RNA polymerase.
the mRNA then detached from the DNA and move into cytoplasm.
In cytoplasm, translation occurs when ribosome come and bind with mRNA to form amino-tRNA complex . Then it will pair with the initiation codon of mRNA. The initiator codon is AUG.
amino-tRNA complex pair with mRNA codon next to AUG. Amino acid is transferred to ribosome linked to 1st amino acid by peptide bond. Ribosome move from one codon by one codon till 3’ end. At each codon amino acid-tRNA complex with correct anticodon pair with mRNA codon on ‘A’ site. Amino acid transferred by tRNA to ribosome is linked to elongation of polypeptide. tRNA on ‘P’ site detaches and process repeats. The polypeptide synthesis end when ribosome reaches the terminator codon, UAA.
The first amino acid is cut from polypeptide. One completed polypeptide will now detached from ribosome and mRNA. Ribosome detached from mRNA and can be used again.
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