Question

Haploid yeast cells that preferentially repair double-strand breaks by homologous recombination (rather than by non-homologous end joining) are especially sensitive to agents that cause double-strand breaks in DNA. If the breaks occur in the G1 phase of the cell cycle, most cells will die; however, if the breaks occur in the G2 phase, a much higher fraction of cells survive. Why do you suppose this is?

Answer 1

When the breaks occur in G1 phase of cell cycle most cells will die. And if it occurs in G2 phase most cells survive because survival of cells at G2 phase depends upon its ability to seal double - strand breaks, which in turn depends upon availability and efficiency of repair enzyme.