Quality Center is one Test Management Tool.  By using this
tool, test cases can be designed, executed and defect can be
reported.

Quality centre supports the businees process requirements 
which were supplied by the customer, where as it can not be 
done through Test Director.

if i am wrong correct me...

Please be clear while posting a question. This helps anyone 
to answer better. 

QC can mean Quality center and also Quality Control. 
Although it is clear that you were talking about quality 
Center, being clear while asking the question helps us 
guess at which level we should answer the question.

Poornachandra - Yes. Requirements can be handled using Test 
director as well.

Hopethathelps,
Itsalleasy

Hai CAHH,

 This is chandana i am very clear about my question,this is 
the one interview question what i faced, even two of them 
gave answers with out any confustion, i think u have to 
think about u r knowledge.If u know the ans post it other 
wise........

This is to chandana

Mr. CAHH was trying to help you, i dont agree you being soo 
rude to him. I do agree with his point, when you are 
posting a question make sure you dont use any short cuts. 
This is only a request

CK

Hi Chandana,
Mr.CAHH is trying to gv u answer then wh u behabe as a Rude.
First thing is that if u r know this answer(as u explain 
early that two of them they told u answer in Interview), 
then why r u posting ur question here.
First try to behave well...ok...
Rajesh.... (Pune)(Jai Maharashtra)

this is not a properway to give the ans ,plz suggest 
correct ans u r simply chating

Question is not clear ....I don't know whether its qulaity
control or  quality centre ...Guys,when you are posting  the
question,make sure that don't give any shortcut words...It
would lead to confusing us ...don't forget while answering also

WOW a simple question and the message board police come out 
and make the intial guy asking the question look stupid.

If you know the answer, then answer, if you dont know they 
answer keep your judgements to yourself.

In terms of QC and Defect Tracking Systems..

Defect Tracking systems specialize in communicating info 
related to software issues (bugs, features, etc) and 
tracking the work done on these as they are related  to 
software releases.

QC or Quality Center is more of a Application Test 
management tool that allows for entering requirements, 
creating test cases and associating with requirements, 
entering defects, testing items, reporting on testing 
metrics.

QC is not a very effective Defect Tracking tool.  Most 
defect tracking tools track more that defects.  They are 
commonly referred to a issue tracking tools.