Gene Therapy for Cancer Treatment - Biotechnology and Your Health: Pharmaceutical Applications - page 103

Figure 7.3 The cell cycle is illustrated in this figure. Cell division proceeds through
discrete phases: G 1 during which the cell grows and prepares for division; the S phase
where the DNA content and chromosomes double; G 2 where the cell develops the
structures needed for cell division; and the M phase where the nucleus splits into
two and the cell divides into two daughter cells.