Indeed, quarks are subatomic particles. They are considered elemantary particles. Protons and neutrons are made up of three quarks each. There are six kinds of quarks knows as up, down, top, bottom, strange and charm. Protons have two "up" and one "down" quarks, whereas neutrons have two "down" and one "up". For more info on subatomic particles, you can try checking out http://particleadventure.org/particleadventure/