How do ribosomes make proteins?
Actually, ribosomes are just the sites where proteins are made. mRNA and tRNA makes the polypeptides. This protein synthesis is divided into two stages, transcription and translation,
- In transcriptions, *
-DNA unzips and inwards as hydrogen bonds between the break.
-Free RNA nucleotides pair up their complementary base with just one of the the exposed strand.
-RNA polymerase helps to link the RNA nucleotides' sugar and phosphate groups between their neighbouring nucleotides by forming sugar phosphate backbone.
-So, a new mRNA (messenger RNA) is formed which is single stranded and it leaves the nucleus.
THIS PROCESS INCLUDES mRNA copying the codes and the information from the DNA
-Also in the nucleus there are free tRNA ( transfer RNA) which have three unpaired bases ( anticodons ) at one end and at the other there is an amino acid attachment site.
-This tRNa attaches to the specific amino acid and then moves towards the ribosomes.
-The mRNA molecule gets attached to the ribosome (smaller unit ) and exposes six of its unpaired bases to the largest subunit at a time.
-The anticodon of tRNA molecule binds with complementary codon and again another tRNA molecule arrives and this also binds with another codon.
-The amino acid lie along each other and former peptide bond after which the tRNA leaves.
-So the ribosome moves along way and many tRNA molecule transport the correct amino acid to make the correct sequence which is to be formed and only stops when mRNA shows 'STOP' codon.
So there is a chain of polypeptide which is synthesised by copying the DNA and this is how proteins are made.