Different Ways Organisms Use Atp Essay

752 WordsMay 3, 20144 Pages
Different ways organisms use ATP ATP is a source of energy used for many different processes. ATP provides an immediate source of energy in a cell and is synthesised from ADP + Pi. One way in which organisms use ATP is for active transport. In active transport, molecules are moved from a low concentration to a high concentration. One example of where this would occur is glucose absorption into the blood. In active transport, once molecules have bound to carrier proteins, ATP binds to the protein and is broken into ADP and Pi. This provides energy for the protein molecule to change shape and open to the other side of the membrane. This moves molecules against the concentration gradient. ADP and Pi then recombine and cause the protein to revert back to its original shape. This process means that molecules can move against a concentration gradient so more glucose and other substances can be fully absorbed. Active transport is also used in neurone cells to maintain a resting potential where the outside of the cell is positively charged compared to the inside. The sodium Potassium pump moves 3 sodium ions out of the neurone for every 2 potassium ions moved in. This is against the concentration gradient so requires ATP to move them via active transport. ATP therefore maintains a resting potential and allows an action potential to occur. In addition to this, ATP is also used during muscle contraction. Muscles contract by actin and myosin filaments sliding past each other. When an action potential stimulates a muscle cell, an influx of calcium ions into the sarcoplasm from the sarcoplasmic reticulum bind to troponin. This causes troponin to change shape and moves tropomyosin out of the way. This allows myosin and actin to bind forming a myosin-actin cross bridge. Calcium ions also active ATPase which breaks ATP into ADP and Pi. The energy released from this moves the

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