There are two major checkpoints in the cell cycle. The first is at?
Thank you for using the Jiskha Homework Help Forum and here are some sites for you to visit:
1. http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/CellCycle.html
2. http://www.ncbi.nlm.nih.gov/books/bv.fcgi?db=Books&rid=mcb.section.3575
3. http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&FOCUS_SPECIES=%20sapiens&ID=69620&
4. http://www.cellsalive.com/cell_cycle.htm (Interactive Animation!)