The cell size doubles in a stage of cell called
1. G1 (first gap) - cell grows and functions normally. During G1, the large amount of protein synthesis occurs and the cell grows (to approximately double its original size) - a number of organelles are produced and the volume of the cytoplasm increases.
2. S (synthesis) - the cell duplicates its DNA
3. G2 (second gap) - the cell resumes its growth in preparation for division