All parabolas are vaguely "U" shaped & they will contain a highest or lowest point which is called the vertex. 

Parabolas might open up or down and may or may not contain x-intercepts and they will always contain a single y-intercept.

Note as well that a parabola which opens down will always open down & a parabola which opens up will always open up.  In other terms a parabola will not all of a sudden turn around and begin opening up if it contain already started opening down.  Alike, if it has already begun opening up it will not turn around and begin opening down all of a sudden.