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The saturation curve of haemoglobin shows positive cooperativity. Initially, the porphyrin ring of the haem prosthetic group in haemoglobin is dome-shaped. When one molecule of oxygen binds one of the fou...
Myelination of an axon makes propagation of action potentials along it much faster. In unmyelinated axons, the action potential is constantly regenerated by active propagation, with the depolarisation cau...
The end walls are removed from each end, forming an uninterrupted tube, so water can pass through easily.Their walls are thickened with a woody substance called lignin, w...
When the neuron is stimulated, it causes rapid depolarisation of the cell surface membrane. This will not generate an action potential unless it is large enough to exceed the threshold potential...
dilute harmful substancestransport in bloodstream and plantsfor metabolic reactions to occurseparation of substancesabsorption of ions etc.
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