7475 IC strange behavior
Yo will need to have a series resistor one the LED since LED's are current mode devices and are some what less compliant wrt to Voltage.  To size that properly you need to know the LED forward voltage, maximum current and also the maximum current possible out of the IC.  Additionally if you what the light to go on when Q1 is high then the current must flow from the pin through aLED resistor combination and into ground.  You have it wired to the Vcc.  When Q1 is high there is no voltage drop across the LED.

There are similar posts around that will show you how to size the resistor.