Final answer:
If licensing occurred during the S phase of replication, it might result in genomic instability, duplication errors, and risk of disease due to the possibility of origins being re-replicated. It could also activate the DNA Synthesis Checkpoint, preventing the cell from advancing to mitosis until the error is resolved.
Step-by-step explanation:
Consequences of Licensing During S Phase
If licensing occurred during the S phase of replication, it could potentially lead to problems with the regulation of DNA replication. Normally, a strict licensing procedure at the G1 phase ensures that replication originates only once per cycle in specific regions of the DNA called origins. If, hypothetically, this process occurred during the S phase, it would interfere with ongoing replication processes and may cause re-replication at origins which could lead to genomic instability, duplication errors, and a risk of inappropriate gene expression. Such an occurrence can have profound consequences on the cell's integrity, potentially leading to cell malfunction, cell death, or diseases such as cancer if mutated DNA is passed down during cell division.
The DNA Synthesis Checkpoint plays a critical role during the S phase by ensuring that DNA has been replicated correctly before allowing the cell to proceed to mitosis. If licensing were disrupted during this phase, it might trigger the checkpoint controls and prevent the cell from progressing to the next stage of the cell cycle until the error has been corrected. Every phase and checkpoint in the cell cycle is intricately regulated to protect the integrity of the cell's genome and ensure the proper functioning and reproduction of the cells.