Energy Systems Flashcards
What is energy and how does it manifest in the body?
Energy is a property of mass and radiation which manifests as a capacity to perform work. It manifests through movement, cell function and maintenance of life.
What is the function of myofibrilar ATPase?
Enzyme that catalyses ATP breakdown, located in the myosin head. The energy is used to release the myosin head from the actin site in muscle contraction.
Name the 3 energy systems
ATP-PC system (anaerobic), lactic acid system (anaerobic) and aerobic system (aerobic)
Explain the characteristics of the ATP-PC system
Capacity of 55-95 mmolATP/kgDM, power of 9 mmolATP/kgDM/s, short and fast exercise (sprinting, jumping, throwing), powerful, small capacity, produce energy quickly but fatigue quickly
Explain the energy yield of the lactic acid system
Glycolysis converts glucose to pyruvate, requires an input of 2 ATP but produces 4 ATP, energy yield of 2 ATP per glucose converted to pyruvate
Explain the characteristics of the lactic acid system
Capacity of 190-300 mmolATP/kgDM, power of 4.5 mmolATP/kgDM/s, larger capacity than ATP/PC system but still limited, moderately powerful, acetyl CoA produced in presence of oxygen, lactate produced when no oxygen is present
Explain the aerobic energy system
Pyruvate enters tricarboxylic acid cycle (TCA) as acetyl CoA, TCA cycle occurs twice for each glucose molecule, produces small amount of energy but a large amount of reduced coenzymes, acetyl CoA is common entry of carbs, fats (beta oxidation) and amino acids into the TCA cycle, coenzymes produced enter electron transport chain
Describe the graph (CHO and fat contribution against aerobic power)
Association between exercise intensity and fuel utilization, at rest it is predominantly fat stores with very little CHO utilisation, as intensity increases CHO utilization increases while fat utilization decreases, at 75% aerobic power CHO takes over from fat as the predominant energy source
