I have 2 questions:

1. The USB differential pair D+/D- are impedance-controlled 90 Ohm transmission line.. Why do I need to put a 22 Ohm series termination resistor in it? Isn't that a discontinued resistance in the transmission line that could technically cause reflections?

2. should I implement TVS diodes on USB and I2C data lines? Thanks

I have 2 questions:

1. The USB differential pair D+/D- are impedance-controlled 90 Ohm transmission line.. 
   Why do I need to put a 22 Ohm series termination resistor in it? Isn't that a discontinued resistance in the transmission line that could technically cause reflections?

2. should I implement TVS diodes on USB and I2C data lines?

Edit: I'm using STM32L152CB-A MCU, the I2C will be user to communicate with some ICs on the PCB itself, and the USB will be used to communicate with a computer which will act as USB host.. I'm using USB2.0.

Thanks