Hi, my assignment is as follows

"Design a buzzer to be used on a game show. 3 contestants each have a button to depress if they would like the opportunity to answer a question.

Features
- Once button is depressed, all other buttons must be ignored (dismantled).
- An LED is illuminated to indicate that a button was depressed and the LED shall stay lit for 5 seconds.
- System may be reset by the operator or automatically.
* Bonus - if contestant answers incorrectly, their button shall be blocked until reset"
​

Here is my circuit, please tell me if you think it will work. Thanks for reading.

 

What function does the transistor serve?

What will debounce the switches?

 

I don't think switch bounce would play into it, since the first pulse in a "bounce string" would be all that is needed to trigger. Debouncing could be added for fussy gates or extra credit, though.

I am unsure of the bonus question of "leave button disabled for rest of round". What determines "rest of round"? I've not watched the show.

 

The master reset enables all switches for the following question and the transistor drains the cap completely disabling that contestants counter until the next question/time the master reset switch is pressed enabling their button for the up and coming question.

What about the rest of it?

 

Check this guy's circuit. It's mostly what you want, except from the disable functionality.
http://forum.allaboutcircuits.com/showthread.php?t=46830

You might want to to away with the transistors, as they will ruin the reliability and energy consuption of your circuit. Try to play a bit with the disable fucntion of the 7447 or the FF IC.