Define Primary Transport
Primary transport employes energy directly, light or chemical energy is transformed to electrochemical energy as electrochemical potential of the substances to be transported. This type have photosynthetic electron transport, light driven ion pumps, redox energy - dependent respiratory chains, transport ATPases and sodium pumps using decarboxylation energy. Not like primary transport, in secondary transport, the electrochemical energy originates from the electrochemical potential of another substance which is used up in symport (the transport of two different molecules or ions in the same direction by a membrane using a common carrier mechanism).