1. The re-synthesis of ATP to provide energy.
The Energy Systems
Learning Objectives:
Don’t leave the room today unless you have learnt:
The re-synthesis of ATP to provide energy.
How this takes place through the bodies 3 energy systems.
The structure of the Phosphocreatine (ATP-PC) System.

2. p p p adenosine ATP ATP = adenosine triphosphate.
ATP is the body’s only useable source of energy.
Although we have other energy rich compounds like phosphocreatine & glycogen, ATP is the only one that can be utilised by the muscles to create movement. p
The bonds are high energy!
adenosine p p

3. How ATP provides energy:
The problem is we only have enough stored to last for about 2 secs of exercise. So to maintain exercise beyond this we have to re-synthesise it.
ATP ADP + P + Energy
ATPase p
adenosine p p
energy

4. Key Questions 1. Where do you think the energy is stored?
2. What is present to assist in the breaking of the bond?
3. What does this release and how is this seen?
ATP ADP +P + ENERGY
This is exothermic which means it gives out energy.
ADP + P + ENERGY ATP
This is endothermic which needs energy to proceed.
This is called a coupled reaction. Why?

5. ATP Re-Synthesis
As ATP stores are low in our bodies it has to be re-synthesised to allow us to keep exercising.
This is achieved by the three energy systems:
The phosphocreatine system.
The lactic acid system.
The aerobic system.
What is it that determines which system is dominant?
The systems don’t work independently as two could be working at the same time to re-synthesise ATP.
Remember the amount of ATP re-synthesise done by each system depends on the intensity of exercise

6. The Phosphocreatine (ATP-PC) system.
This system uses another high energy compound known as phosophocreatine to provide necessary energy to combine ADP and P.
High energy
bond 1.
Creatine
kinase
Creatine P
Exothermic reaction?
Energy (to re-synthesise 1 molecule of ATP)
Creatine P
&

7. 2. Energy (from diagram 1) 3. Energy for exercise!!
Endothermic reaction? 2.
Energy (from diagram 1) P P
Adenosine P 3.
ATPase P P P
Adenosine
High energy bond
Energy for exercise!!

8. PC P & C & energy energy & P & ADP ATP Coupled Reaction
Creatine kinase
PC P & C & energy
energy & P & ADP ATP
A coupled reaction is when the energy produced in the first reaction is used in the second reaction.

9. Summary. Can you complete the analysis table for the ATP-PC system?
The energy systems don’t make ATP, they produce enough energy to re-synthesise ATP.
What are the advantages and disadvantages of the ATP-Pc system?

10. ATP is a most important compound
ATP is a most important compound. Explain why ATP plays such a major role during physical activity. (4)
Jan 05:
3 marks
1. The only usable form of energy in the human body/energy currency that powers all forms of biological work/immediate
2. A high energy phosphate compound/the outer two phosphate bonds are high energy bonds/a store of potential energy
3. When the terminal phosphate bond is broken energy is released/ATP is broken down to release energy/ ATP ADP + P + ENERGY
4. An exothermic reaction
5. Facilitating enzyme is ATPase
6. Can be resynthesised (via the energy systems/with or without oxygen)
7. The breakdown and resynthesis of ATP is a reversible reaction/
ATP ADP + P + ENERGY

11. Define the terms energy, work and power, giving the units of measurement for each. [3] Jan 05.