from what i remember (it’s been a few years since i studied this stuff lol) you can only arrest the cell cycle (dismantling -> duplication of chromosomes -> separation of chromosomes -> completion of division) at specific points, and can’t go in reverse. Theres a whole cascade of signals, that when started, are running their way to specific checkpoints. if a cell is stuck for too long at any checkpoint, it commits suicide, because that’s THE sign for unrecoverable DNA damage. And if a cell starts ignoring checkpoints and suicide signals, it’s called cancer.

Many antibiotics work that way btw - they look a lot like nucleotides (A C G T), but if a bacterium adds them when copying instead of one of the “letters”, the machinery gets stuck, and the bacterium cant divide anymore. That gives the immune system time to kill them off. Bacteria replicate a lot and have no proofreading of what they are copying, so they are susceptible to this. Animal cells have proofreading AND the ability to correct an error, so we are fine.

I loved studying this stuff. i did NOT love the crapload of chemistry i had to learn, but even that was highly interesting.