Quarks :

Quarks are elementary sub-atomic particles and a fundamental constituent of matter.
Quarks combine to form protons, neutrons and mesons.Particles formed by the combination of Quarks are hadrons.
Hadrons are of two types :
1)Baryons.
2)Mesons.
Particles consisting of 3 quarks come under Baryons.Protons and Neutrons come under the baryon family.
Particles consisting of a quark and an anti-quark come under the Meson family.
Assumptions on the existence of other hadrons like tetraquarks (Exotic mesons) and Pentaquarks(Enotic baryons) have been made but their hardly exists any evidence to support the fact.
Quarks are divided into six types which are known as the six flavours : up, down, strange, charm, bottom and top.
Up Quark and Down Quark are the most stable of all the Quarks and are also the most commonly found quarks. They also hold the lowest masses of all the quarks.

If a particles exists, it's anti-particle is sure to be found.  Every quark has a corresponding anti-particles known as the antiquark. Quarks and Antiquarks differ only in few properties. They posses same magnitude but have the opposite signs.

The Quark Model was proposed by Murray Gell-Mann and George Zweig in 1964.

Of all the quarks, top quark was the last to be discovered.

A proton, a part of the Baryon family has 3 quarks. Two up quarks and one down quark and a Neutron posses two down quarks and one up quark. 

Types of Quarks. 

Neutron

Proton