What exactly is a transponder key?
These days, most car keys come with a “chip” inside of the head of the key.  This is called a transponder key blank.  The word transponder is short for transmitter/responder.  This transponder chip that is imbedded in the head of your car key keeps the car from being started unless the chip has been programmed.  Some also call the transponder chip a disabler since the chip actually disables the car from being started if it is not programmed.
In order to have these transponder (chip) keys programmed you will need to take the key to your local dealer or to a pro automotive locksmith.   There the professional can “program” your key (transponder chip) to match your car’s ignition code.  Usually you will have to provide the dealer or the locksmith with proof of ownership of the vehicle before they will program and cut your new key.
The important thing to remember with a transponder key is that is not enough just to have it cut you must also have the transponder chip programmed so you can start your car.  If you have the key cut and not programmed it will unlock the car and turn in the ignition, but it will not turn over the ignition start.