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Respiration – A2
A Stangroom
Life requires a continuous supply of energy.
Organic molecules can be used as building blocks or as potential chemical energy which is released from the breakdown of molecules in respiration
This energy is used to do work
Energy is required in the form of ATP
ATP ADP + Pi + 30.5 KJ mol-1
ADP AMP + Pi + 30.5 KJ mol-1
AMP Adenosine + Pi + 14.2 KJ mol-1
ATP + H2O ADP + H3PO4 + 30.5 KJ mol-1
At rest an average person uses 40Kg of ATP in 24 hours only 5g is present at any time
During exercise ATP is broken down at the rate of 0.5g per minute
ATP is the universal intermediary moleculebetween energy yielding and energy requiring cell reactions energy currencytransfer is inefficient; some is lost as thermal energy
Energy storage molecules are:Long term: glycogen, starch, fatShort term: glucose, sucrose
Energy is required for WORK :
Anabolic reactions (synthesis) e.g. amino acids proteins
Active transportMovement against diffusion gradient e.g.sodium/potassium pump
Movementcilia, flagella, cytoplasmic streaming and muscles Energy is used to bring about the movement of two protein strands relative to each other
Muscle made of muscle fibres, made of bundles of myofibrilsThey are elongated cells containing myofilaments – actin and myosin
actin (thinner) and myosin (thicker) are protein strandsThe cells also have many mitochondria And specialised ER called sarcoplasmic reticulum which releases calcium
Myosin has a rod shaped region attached to a globular head that acts as ATP-ase the head can attach to actinActin is made of two helical protein strands twisted together
myosin
Actin