if I take the micro controller (ATmega328P) from the Arduino board and simply place it on to a breadboard, do I still need to upload the boot loader ?
No, you don't need to upload the Bootloader, it's already in the chip.
BUT, when you unplug the ATMega328 you no longer have the serial connection support over USB.
If you upload a sketch while the ATMega328 is on the Arduino board and then put it in a breadboard, it will work providing you don't need serial/USB and you have the correct oscillator (16Mhz) on your breadboard.
There are a couple of approaches to create your own breadboard projects:
Keep your Arduino intact and buy some ATMega328 chips. You can use the Arduino as an ISP to program the chips without needing a serial/USB connection.
Use an Arduino Nano. This plugs directly into your breadboard and has everything you need onboard.
Start reading here, this has all been done before.
No, the bootloader is already installed. You will need a 16 MHz crystal, two 22pF caps, a 10K resistor (reset pullup), and four 0.1uF caps - one for Vcc, one for Avcc, one for Aref, and one for DTR if you plan to add a 6-pin header to plug an FTDI Basic (or equivalent clone) for downloading code via the Arduino IDE, or use the serial port for debugging your code with the serial monitor - basically the same as a Promini less the 5V regulator.
Do not connect Aref to 5V - just the cap to Gnd.
If you want to program it using the Arduino tools you need the boot-loader. (which boot-loader will be present if you removed the ATMega328 from an Arduino board)
If it is already progammed you don't need the boot loader If you intend to use a SPI programmer (eg: AVRASP) then you do not need the boot loader.