The Biochemitry of Human Energy systems

Essay by AndyWhalleyUniversity, Master'sA+, February 2003

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a.With the aid of diagrams provide a summary of how the following energy systems work.

Energy systems; introduction

Energy systems are cellular levels processes used to produce Adenosine Triphosphate (ATP) figure 1. This is an adenosine molecule linked to three high-energy phosphates that acts as an energy store for the cell. The energy is released when ATPase, an enzyme, reacts with ATP to produce ADP and Pi, e.g.


There are three energy systems that do this;

·The Creatine Phosphate System

·The Glycolytic or Lactic Acid system

·The Oxidative system (The Krebs cycle, Citric Acid Cycle or Tricarboxylic Acid Cycle)

The first too are ANAEROBIC, the third is AEROBIC.

I.Creatine Phosphate (CrP)

Summary: A cytoplasm based catabolic reaction in which Creatine Phosphate is degraded to Creatine to provide ATP; net profit of one ATP molecule; can proceed anaerobically.

Net reaction:

CrP + ADP+H+--->ATP + Creatine


During high-intensity exercise energy for ATP resynthesis is provided primarily by another high-energy phosphate compound called creatine phosphate (CrP), see figure 2.

Cellular concentrations of CrP are 4-5 times greater than that of ATP and are generally concentrated in areas of contractile protein; skeletal muscle has 95%. CrP is like a match; when the muscle receives a nerve impulse from the brain instructing it to contract, it instantly releases its energy, as if the match had been struck.

This gives a natural "reservoir" of energy to enable resynthesis of ATP to occur rapidly, 7Toler (1997), 8Vandenberghe (1996) and 9Feldman (1999), but it can only sustain work at maximal levels for about 5 - 15 seconds dependant on activity level and the individual's personal physiological adaptations to exercise.

The system has two steps. Firstly, bond between creatine and phosphate splits energy is liberated, as CrP has a higher potential energy...