So I like to think of the G1 and G2 stages as the "G"rowth stages of the cell. Similarly, the S stage is the DNA "S"ynthesis stage. In experiment 2, the cells are still dividing but are just smaller than normal. This means that they didn't get sufficient time to grow prior to mitosis. This affects the G1 and G2 stages. The S phase is likely unaffected because DNA synthesis still has to happen before the cell can divide and the cell can only do it so fast.