I mean, how many bits or bytes represents 1 satoshi, the minimun bitcoin portion and how many bytes represents one entire bitcoin, not a block, a 1.00000000BTC
Bitcoin amount is simply a number in the outputs of transactions, bitcoins themselves don't really exist. For example, in this transaction, there is this output:
Value is the number of satoshis in the output, these output values are the only representation of bitcoins on the blockchain.
There is actually no such an object as a Bitcoin (or a satoshi, or any unit used in Bitcoin). Thus there are no data structures which represent "a Bitcoin".
How Bitcoin actually works is by creating and spending from previous transaction outputs. The amount of Bitcoin is simply just a value assigned to a transaction output.
The blockchain contains the transactions, and each of those transactions contains transaction outputs which it creates, and references to other transaction output which it spends from. That is the data that is stored on your hard drive.