A section of mRNA coding for a functional polypeptide is shown below:
mRNA: 5'- ACU - CCU - GAG - GAG - 3'
A point mutation occurred in the template DNA strand, resulting in the third mRNA codon changing from GAG (glutamic acid) to GUG (valine).
The genetic code lookup for the relevant codons is as follows:
ACU codes for ThreonineCCU codes for ProlineGAG codes for Glutamic acidGAA codes for Glutamic acidGUG codes for ValineGUA codes for ValineName the type of covalent bond present in the primary structure of a protein that links successive amino acids.
Outline the role of RNA polymerase in the synthesis of this mRNA molecule.
State the base sequence of the anticodon on the tRNA molecule that pairs with the mutated codon GUG.
Explain how a mutation that changes the third codon from GAG to GAA would affect the final tertiary structure of the protein. Refer to the degeneracy of the genetic code.
In contrast, a mutation changing GAG to GUG replaces glutamic acid (hydrophilic) with valine (hydrophobic). Explain how this substitution can alter the tertiary structure and biological activity of the protein.