How are amino acids brought to the cellular site where translation takes place? What is an anticodon?
Amino acids are brought to ribosomes by RNA molecules known as transfer RNA, or tRNA. One tRNA associated to its specific amino acid binds by a special sequence of three nucleotides to a mRNA codon exposed in the ribosome. This sequence in the tRNA is known as anticodon. The tRNA anticodon must be complementary to the mRNA codon to which it binds, according to the rule A- U, CG. The ribosome then slides along the mRNA molecule (a process called translocation) to expose the following codon to the binding of other tRNA. When amino acids corresponding to neighboring codons bind by peptide bond the first tRNa is liberated.
