Change color of cell dependent upon color of another cell

I have a task list table. Cell A1 is a checkmark cell. Cell B1 is a description of a task (i.e. clean car). I want both A1 and B1 cells to be filled red if A1 is not checked but have no fill if A1 is checked. How do I do this? I know that a A1 check mark box that is checked = TRUE and not checked = FALSE but don't know how to create a if/then formula that can affect cell B1 (i.e. highlight B1 red if A1 is checked) without disturbing the text that I write into B1 (i.e. clean car, go grocery shopping, feed dog, etc). Any thoughts?