What are two main reasons that prevent cells from growing so large?

answer:a previously unknown mechanism within the cell growth cycle that controls cell size. They made this fundamental finding by studying yeast cells, but it could provide insight to basic human biology as well as diseases such as cancer that thrive by manipulating this mechanism.

Cells of all types seemingly “know” just how large to grow, and when they reach that determined size, they divide into new cells. With no clear answer for what triggers this cellular decision, Jan Skotheim, an associate professor of biology at Stanford University, began searching for the mechanism nearly a decade ago.

Explanation: sorry  if i'm wrong

not sure if this what   you'r looking for would be percent composition

the three components of a nucleotide are the nitrogenous base, the phosphate group and the five-carbon sugar.