Purchasing houses with mortgage?

So I am learning about real estate and have a question about mortgages on houses. I am 18 and know very little so bare with me.

I have 2 scenarios, please answer both!

1) Home valued at 200k, current loan balance at 50k. If I bought this home with all cash for 200k would the sellers receive 150k and then the bank would get 50k?

2) Home valued at 200k. Home was refinanced when loan balance was at 50k and now the current loan balance is 225k. If I purchase this home with all cash for 200k at the market value then what happens to the other 25k? Do the sellers continue to pay that off or would I have to pay it off now that I own the home?

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