How are step-up and step-down transformers used in the transmission of electric current from the electric company to homes?

(This is what my teacher said, I wrote this down in my notes) The answer is, Step-up Transformers are used to increase the voltage of an electric current before it is sent out over transmission lines from the electric company. Step-down transformers are used to reduce the voltage of current from high-voltage transmission lines before it enters homes and businesses. Some devices, such as televisions, contain step-up transformers that increase the voltage once again.