Bit of a noob question regarding gas.

Hi all, I've got a small amount (~0.1ETH) sitting in a wallet that I'd like to send to my Binance account. Now, I've read that simple transfers usually only take around 21,000 gas to send, give or take a little. However, transfers to "smart contract addresses" can use in excess of 800,000 gas! I guess I have two main questions:

1) What is a "smart contract" address, and how does it differ from a regular wallet?

2) Is Binance considered a "smart contract" exchange, and will I be slammed in gas fees for sending my ETH there?

Thanks in advance for any help.