What would go wrong if a cell did not replicate its dna before beginning mintosis?

If a cell did not replicate its DNA (during the S-phase) before beginning mitosis, then the two identical daughter cells would only get one chromosome from each pair. This, instead of the normal (diploid) 2 pairs of each chromosome (2×23=46), would lead to two haploid cells with 23 total chromosomes each. They would be unable to function and sustain life, thus would likely die soon after division.

Because they are stupid and insensitive