Answer the following question given this paragraph: 

During active transport, specialized integral membrane proteins recognize the substance and allows it access. Essentially this process is forcing a ion or molecule to cross the membrane when normally it would not. Moving a substance against its concentration gradient is known as primary active transport , and the proteins involved in it as "pumps". This process uses the energy of ATP. In secondary active transport , energy from an electrochemical gradient is used to transport substances. This process involves pore-forming proteins that form channels through the cell membrane.


Q: What phenomenon involves the forcing of a substance into a cell against its concentration gradient?


A:
primary active transport