<P> Active transport is the movement of molecules across a membrane from a region of their lower concentration to a region of their higher concentration--in the direction against the concentration gradient . Active transport requires cellular energy to achieve this movement . There are two types of active transport--primary active transport that uses ATP, and secondary active transport that uses an electrochemical gradient . An example of active transport in human physiology is the uptake of glucose in the intestines . </P> <P> Active transport is the movement of molecules across a membrane from a region of their lower concentration to a region of their higher concentration--in the direction against the concentration gradient or other obstructing factor (often a concentration gradient). </P>

What are the key features of active transport
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