Given the mrna sequence ggu-gcu-ccu-auu, what would happen if a nucleotide was added at the fourth location in the chain? a. chromosomal mutation b. frameshift mutation c. substitution mutation d. deletion mutation

The correct answer is B) Frameshift mutation.

The given  mRNA sequence is GGU-GCU-CCU-AUU. When a nucleotide is added at the fourth location in the chain, it entirely changes the frame from the insertion of the nucleotide till the end of the gene sequence. This is called a frameshift mutation.

This is because after adding a nucleotide, a new frame is generated that will code for different amino acids and therefore a different protein will be synthesized.

On the contrary, chromosomal mutation is an abnormality in the chromosome ( in terms of number or structure) whereas substitution mutation is the one, which exchanges one base with another. Deletion of base also results in the frame-shift mutation.