Question

what will happen to the cell if its nucleus will be removed

Answer 1

The nucleus ,in case of eukaryotes is considered to be the 'brain of the cell'. so if the nucleus is removed the cell will die.

Answer 2

Since the nucleus is known as "the brain of the cell", if it were removed, the cell would die almost instantly. The nucleus controls all of the cell organelles. So, if it is removed there will be no organisation in the cell (i.e. everything will go hapazard); the cell will not meet its essential requirements and therefore it will die.