ENERGY SYSTEMS A2 Physical Education

‘The Energy Currency’ Sometimes known as a nucleotide. Chemical compound containing base (adenine) a sugar (ribose) and phosphate groups (bonded to the sugar).

Storing energy Energy ‘trickling’ into your body from the digestion of food ATP PCr Blood Glucose Muscle and Liver Glycogen Fat (lipids) Protein 2 s 2–10 s 503 g (2012 kcal) g ( kcal) ? Re supply of energy

ATP – Role Adenosine triphosphate (ATP) is the ‘energy currency’ of the body – it transfers energy from one molecule to another. All energy transfer within the body uses ATP (e.g. storage of glycogen and mechanical work for exercise). Without ATP work cannot be carried out – it must be constantly replenished. Each cell of the body has about a billion molecules of ATP which are used, re-formed and reused… and so on… Energy transfer via ATP is controlled by the enzyme ATPase.

ATP Consists of an adenine molecule, a ribose molecule and three phosphate groups bonded together. Energy for forming ATP comes from the catabolism of glucose (known as cellular respiration). ADP + P + Energy = ATP

ATP Splitting – adenosine diphosphate ATP + ATPase = ADP and energy ADP + P = ATP The extra P comes from the Creatine Phosphate (CP) energy system. Hydrolysis (splitting) of ATP liberates 7.3 kcal of energy. Draw on board

Coupled reactions Coupled reactions occur in pairs. The breakdown of one compound provides energy for building another compound. For example, if glucose is broken down the energy is stored as ATP.

Redox reactions – at the smallest level Transfer of energy occurs via oxidation and reduction reactions (or redox reactions). Oxidation is the removal of electrons from a molecule decreasing potential energy. Reduction is the opposite: accepting an electron from elsewhere resulting in an increase in potential energy. This usually occurs when dehydrogenase enzymes accept electrons from hydrogen: –NAD (Nicotinamide Adenine Dinucleotide) –FAD (Flavin Adenine Dinucleotide)

Exothermic and endothermic reactions Exothermic (also known as exergonic) –Produce more energy than they consume (give off energy) –E.g. break down of complex molecules to smaller ones –Such as: glycolysis, Krebs and electron transport Endothermic (also known as endergonic) –Consume more energy than they produce –E.g. combining simple molecules to form more complex ones –Formation of amino acids (peptide bonds) in muscle hypertrophy

The Energy Systems ATP-PCr (immediate) Lactic acid (short-term) Aerobic (long-term) GROUPS: - What do you know about each of these energy systems? - What ‘fuels’ are being used? - Consider duration and intensity of exercise?

The Energy Systems

1.Immediate energy (ATP-PCr system): approx. 6–10 s 2.Short-term energy (Lactic Acid system): approx. 2 min 3.Long-term energy (Aerobic system): more than 2 min Press me

The Energy Systems Immediate:ATP-PCr Short-term: Lactic acid (glycolysis) Long-term:Aerobic

Exam Question 1.With the use of an example for each, explain the terms exothermic, endothermic and coupled reactions. (6 marks)