Not in opening them, but in running them. 1 GB is really not that much.
Open Activity Monitor and go to the System Memory* tab and look for Page Outs and Swap used and report back.
Adding RAM can reduce slowdowns in the machine that happen because of excessive page file use. The more you multitask, the more that the machine has to stop and swap memory space on and off the hard drive. When you have enough memory, swapping is kept to a minimum and the machine can perform to its full potential.
Two GB is a practical minimum for running OSX smoothly. 4 GB would be an even better investment, and your machine should handle that no problem. (you can go as far as 6 GB with this machine)
Apple does not always report the correct maximum amount of RAM, hell, the 2011 MBPs are still stated by Apple to go only to 8 GB of RAM, while they currently can take 16 GB of RAM and theoretically 32 GB of RAM if 16 GB 204-pin DDR3 SO-DIMM RAM modules would be available.