Fill in the blanks.Phosphorylation cascades are similar to a row of dominoes falling down, instead of one domino knocking down the next, a phosphate being added activates the message. In this way, a series of different _______ are each ___________ one after another. Inactive protein kinase 1 gets a _________ added and now it is _________ protein kinase 1. Active protein kinase 1 transfers a _______ and now inactive protein kinase 2 is now ________. This continues until the desired __________ is activated to cause a cellular response.