Question

Genetic Code: The dictionary of the language of life Use the Genetic Code as a "dictionary" to solve the exercises on next page 

5. If a mutation happens in the DNA that changes the T at base 14 to a G: 

a) What would be mutated sequence of nucleotides in the corresponding codon in the mRNA and the anticodon in the tRNA? Is there any change in the corresponding amino acid in the protein?  

b) What is the name of this type of mutation? 

6. If a C were inserted between bases 9 and 10: 

a) What would be the mutated sequence of nucleotides in the corresponding codon in the mRNA and the anticodon in the tRNA? What would be effect of this mutation on the sequence of amino acids in the protein?

b) What is the name of this type of mutation? (1 point)

Answer 1

3’-ATATTACTTTGCATGGACT-5’ DNA

5’-UAUA-AUG-AAA-CGU-ACC-UGA-3’ mRNA

             3’-UAC-UUU-GCA-UGG-ACU-5’     tRNA

                 Met-Lys-Arg-Thr-STOP               Peptide Sequence

Question 5: If we replace T at 14 by G,

3’-ATATTACTTTGCAGGGACT-5’ DNA

5’-UAUA-AUG-AAA-CGU-CCC-UGA-3’ mRNA

             3’-UAC-UUU-GCA-GGG-ACU-5’     tRNA

                 Met-Lys-Arg-Pro-STOP               Peptide Sequence

This is missense mutation whereby substitution of a base in DNA sequence leads to change in amino acid sequence (Threonine into Proline).

Question 6: If we insert C in between bases 9 and 10,

3’-ATATTACTTCTGCATGGACT-5’ DNA

5’-UAUA-AUG-AAG-ACG-UAC-CUG-A-3’     mRNA

             3’-UAC-UUC-UGC-AUG-GAC-U-5’   tRNA

                 Met-Lys-Thr-Tyr-Leu-                     Peptide Sequence

This is an example of frameshift (insertion) mutation whereby insertion of a nucleotide in the DNA sequence changes the whole amino acid sequence from that position. It may affect the protein’s function.