Heres a list of iPod Touch 5 components and in what model of iPhone you'll find them in:
Display: iPhone 5
Connection: iPhone 5
Processor: iPhone 4S
Memory: iPhone 4S
Camera: iPhone 4
Not in the iPod Touch 5:
Compass
Ambient Light Sensor
Phone Capabilities (Obviously)
It's also missing the GPS.
The camera is sort of a hybrid between the 4, 4S, and 5. It's 5 MP like the 4, but it has 1080p video and panorama like the 4S. The front camera takes 720p video like the 5.