Question

when a strand of dna was replicated, one base was left out. why would this be more damaging than if the base was only changed?
the process stops and must restart at the beginning after the new sequence of dna has been read.
the missing base would leave a hole in the new dna strand, causing the structure to be unstable.
the rest of the dna cannot be read, as it would recognize that the number of bases changed
the codons shift one letter for all bases after the mutation, changing all of them as well.

Explanation:

DNA is read in codons (groups of three bases). When a base is left out (a frameshift mutation), it shifts the reading frame for all subsequent bases. This changes all codons after the mutation site. A base - change (a point mutation) only affects one codon. For example, if the original DNA sequence is \(ABCDEF\) (where each letter represents a base and codons are \(ABC\), \(DEF\)). If a base \(B\) is deleted, the new codons become \(AC\) (incomplete) and then \(DEF\) is shifted. But if \(B\) is just changed (say to \(B'\)), only the \(ABC\) codon is affected.

Answer:

The codons shift one letter for all bases after the mutation, changing all of them as well.