Here's how it works:

* Glycolysis is the first stage of cellular respiration, where glucose is broken down into pyruvate.

* ATP is a molecule that stores chemical energy in its phosphate bonds.

* The first step of glycolysis involves the phosphorylation of glucose, adding a phosphate group from ATP. This forms glucose-6-phosphate.

* This process requires energy and is therefore endergonic, meaning it consumes energy. The energy comes from breaking the phosphate bonds in ATP.

So, in essence, ATP provides the initial energy "kick-start" needed for glycolysis to begin.