4. Phosphocreatine is used by your muscle cells to store some energy. The dephos
ID: 196030 • Letter: 4
Question
4. Phosphocreatine is used by your muscle cells to store some energy. The dephosphorylation of phosphocreatine, like that of ATP, is a highly exergonic reaction (see below) Phosphocreatine + HsO = creatine + Pi ATP + Hz= ADP + Pi dGo,--10.3 kcal/mol Gor -7.3 kcal/mol Part A: Write the single coupled reaction from the two above reactions which would result in an overall exergonic reaction. (3 pts) Part B: What is the Ge for the coupled reaction you wrote above? (2 pts) Part C: Without calculating it, what can you say about the K'e for the coupled reaction? (2 pts) Part D: The stores of ATP in your muscle cells provide energy for about 3 sec, whereas stores of phosphocreatine may provide energy for about 15 sec. In what form is the bulk of energy stored in muscle? Why? (3 pts)Explanation / Answer
A. Phosphocreatine+ Water +ATP ----> Creatine +ADP+ Pi
B. The dGo' value is -(10.3+7.3)kcal/mol = -17.6kcal/mol
C.If the value of dGo' is high , then Keq tends to be high.
D. Energy is stored in the muscle in creatine phosphate form. It is utilized when there is faster requirement of energy.