When the cell begins to synthesize genetic material, it is in

 When the cell begins to synthesize genetic material, it is in S phase ( Synthesis phase ) of Cell Cycle.

Explanation: Cell cycle is process which leads to the synthesis of DNA and

formation to two daughter cells.

Cell cycle include two phases -:

1) Interphase -: It has three phases G1  ( this is gap phase where cell grows make organells ), S phase ( where synthesis of DNA takes place ) and G2 phase ( it is the second gap phase ).

2) Mitotic Phase- Formation of two daughter cells.

the endomembrane system i think