Can i transfer/deposit bitcoin from another exchange into my bit coin account for trading purposes? Can I deposit bitcoin from another exchange to be used for trading?
In general you should be able to transfer your bitcoin between any two exchanges for trading.

As an example, you may wish to move BTC from GDAX to Gemini for trading. First you should get you'll need to get a deposit address for your Gemini account. Next you should follow the instructions to withdraw digital currency to an external address from GDAX.

You'll need to have created an account at each exchange you wish to use. You should also make sure that you have completed any required identity checks before you send an exchange your bitcoin. You should also expect transfer fees and possible withdrawal delays. 

I recommend transferring a small amount between exchanges first. You should also try selling that small amount on your new exchange and withdrawing money to your bank account.