can i put .iso on usb and boot from that?

So a friend of mine gave me a .iso of win7. am i able to put that on a USB and then boot from the usb to install it or do i have to burn the .iso to a dvd?

Do i also need to do bootcamp before hand and partition the hard drive? if so, how many gigs should i give to it. will only use it for very limited of things aka steam and other very small programs.

Thanks!


EDIT: Have figured it out!