john25:
We all know that op amps means operational amplifier. But how much amplification can a uA741 can do? Can this op amp amplify upto 1000 times?
An opamp in theory has infinite gain, and you set the actual gain using the negative feedback resistor ladder.
However, over 5,000 or so, I'd start studying data sheets and maybe measurements in detail.
For a signal that varies (e g, almost every signal in existence 
you should also look at the "gain product."
If an opamp has a "gain product" of 2.8 MHz, and you want a 1000 factor gain, then your input signal should be less than 2.8 kHz for best results.