Antisemitism has been defined above by LUHE, as has Islamaphobia. But the latter can descend in to Racism if some people lump all followers of Islam together with the Islamic Extremists who become terrorists, obviously this is wrong.
They do not extend such racism, if you like to call it that, it is really extreme ignorant bigotry, to Christianity, strangely, which has its own extremists who bomb Abortion Clinics etc.
I fully endorse what LUHE said above " Any religion is fair game for questioning, criticising and poking fun at. ".