​A Concentration Gradient is like a hill

​High concentration flows to low concentration, like rolling down a hill--from high concentration--alot of molecules to a low concentration

​Comparison of Hypotonic, Isotonic, Hypertonic

​Hypotonic-- like hypodermic needle, the number of solute/sugar/other molecules is less than what's outside the cell, so water comes into the cell

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​Isotonic--the number of solute/sugar/other molecules equals what's outside--so water is equal.

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​Hypertonic--more solute/sugar/other molecules outside cell than inside so water leaves the cell.