bigantdog RAM holds whatever is on your screen, or any programs/processes running in the background; like your anti-virus of firewall. RAM is volatile which means when there is no power feeding the RAM it is cleared, that is why it is a good idea to restart your computer every once in a while.
Graphics card memory is the same, but graphics card memory does not hold "running" anti-virus software, it only holds textures, pixels etc... anything that is 3D or game related.