Translation
Translation is the process by which the information on mRNA
is used by the tRNA to synthesise a polypeptide chain which will eventually
form a protein. The formation of proteins happens in the ribosomes which can be
situated freely in the cytoplasm or just attached/part of the rough endoplasmic
reticulum. The proteins which as synthesised freely in the cytoplasm are used
by the cell for its various functions, the protein synthesised by the ribosomes
on the rough endoplasmic reticulum often go to the Gogli apparatus before being
released by the cells into the surroundings.
The ribosomes ‘read’ the genetic message on the mRNA while
the tRNA delivers the amino acids in the sequence originally determined by the
template strand of the DNA.
Remember
The structure of tRNA
·
The anti-codon is complementary to the
nucleotides on the mRNA strand and the acceptor strand is complementary to the relevant
amino acid.
The Structure/Role
·
To pick up amino acids from the cytoplasm and to
transfer them to the ribosomes in the correct sequence.
The Process
1.
The codons on the mRNA move the ribosomes from
the nucleus out of the nuclear pores in the nuclear envelope.
2.
tRNA collects the complementary anti-codon
triplet which is situated on the mRNA strand.
3.
The amino acid is put into the right place in
the chain.
4.
The amino acid bonds to the forming polypeptide
chain while the tRNA is released.
5.
The process is repeated until the whole of the
mRNA chain has been translated
The correct sequence from the
original DNA has been transferred and a polypeptide chain has been made.
In the Ribosomes on the rough endoplasmic reticulum after
translation the proteins pass into the cisternae of the golgi. Vesicles are
formed containing the proteins in a concentrated form with the possible
addition of carbohydrates. The vesicles break off abd move to the cell
membrane, the vesicles then fuse with the cell membrane and are carried through
the membrane to be secreted into the surrounding environment.
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