Question

What will happen if plasma membrane ruptures or breaks down?

Answer 1

if this will happen the cell would not be able to  exchange materials from its surroundings by diffusion. the  cell will die as the protoplasmic material will disappear.

Answer 2

$\huge\mathscr\red{Answer}$

As the plasma membrane acts as a mechanical barrier to the protoplasm so after the rupturing of plasma membrane, the protoplasmic contents will be dispersed in the surrounding medium.