Question

When a muscle cell demands energy to perform its work of contraction, what happens to ATP?

Answer 1

ATP is used to return the mysoin to its starting position. Because ATP is used to return the mysoin head to its starting position. The ATP is hydrolyzed to Pi + ADP. The head with the ADP and Pi attaches itself to the actin filament. When ADP and Pi release the mysoin head pulls back. There is now space available for a new ATP molecule to attach itself.