Why is it necessary for the cell to grow and duplicate its dna before the start of meiosis?

If a cell were to begin meiosis without duplicating its DNA, the two resulting cells would have insufficient DNA to develop properly, as there would only be one copy of each chromosome in the first cell, so as division occurs, half of the DNA needed would go to one cell, and half to the other. This means that, as previously stated, there would be insufficient data to develop properly, meaning there would be insufficient data to function. This would most likely result in the cells dying off.

Explanation:

It's necessary so that the cell can replicate all the DNA so that the new cell will receive a full set of DNA.