What is the Smallest piece of information processed by computer?

The smallest unit of memory if this is what your referring to is known as a Bit. from there they get larger. 4 Bits is a nibble. 8 Bits is a Byte. 8 to 96 Bytes is a Word.

1024 Bytes - Kilobyte

1024 KB - Megabyte

1024 MB - Gigabyte

1024 GB - Terabyte

1024 TB - Petabyte

1024 PB - Exabyte

1024 EB - Zettabyte

1024 ZB - Yottabyte