Translation is the process by which the mRNA codon sequence guides the linking of amino acids to form a polypeptide chain on the ribosome. tRNA acts as an adaptor molecule, reading the mRNA code and binding specific amino acids. tRNA has a cloverleaf secondary structure and contains an anticodon loop that binds to mRNA codons. Ribosomes are the sites of translation and consist of two subunits that come together on mRNA, facilitating the ordered interaction of translation components.

1. •What is Translation ?
•Initiator tRNA
•Ribosome
•Translational Unit
•Untranslated Regions

2.  The process by which the triplet codon (base
sequence) on mRNA guides the linking of a
specific sequence of Amino acids to form a
polypeptide chain on Ribosome is known as
Translation (under central Dogma)

4.  Francis Crick proposed that tRNA act as adaptor
molecule ,which could read the code and would
bind to specific Amino acids during translation .
This mechanism was explain under Adaptor
hypothesis.
 tRNA was known before Genetic Code .
 tRNA is also known as soluble RNA(sRNA)
 The tRNA has a secondary structure like clover
leaf ( explain by clover- leaf model)
 tRNA has five arms:
 Anticodon loop,Amino acid acceptor end, T-loop,
D- loop & Variable loop.

7.  The organelle where the process of translations takes place.
 Ribosomes are small, dense, rounded and granular particles of
Ribonucleoprotein.
 They found freely in the matrix of Mitochondria, Chloroplast and
Cytoplasm.
 Or remain attached with the membranes of Rough ER and Nucleus.
 It provide the ordered interaction of all the molecules involved in
protein synthesis.
 Tissieres and Watson (1958) isolated 70S E.Coli ribosome, which cosists
of two subunits :-50S and 30S.
 Ribosome contains ¾ kinds of RNAs and Proteins
 Dimer:-Two ribosomes become associated with each other by high
concentration of Mg++ ions in matrix.
 During protein synthesis many ribosomes are aggregated due to
common mRNA and form Polysomes or Polyribosomes.

12.  70S Ribosome:
 50S +30S subunit
 70S contains: Three types of rRNA
 50S : 23 S and 5 S rRNA + 120 nucleotides.
 30S : 16 S rRNA + 1650 nucleotides.
 About 60% of rRNA is helical and contains paired
bases.
 These paired bases region is due to hairpin loops
between complementary regions of their molecules.

14.  It is the sequence of RNA flanked by the start codon
AUG and the stop codon in mRNA.
 It codes for polypeptide that has to be produced.

15.  These are some additional sequences in an mRNA
that are not translated.
 They are present at both the ends ,that is 5’end
(before start codon ) and at 3’end (after stop codon).
 They improve the efficiency of translation process.