Yes, the private variables are also inherited.
Stopping class from further inheriting: -
We can stop the class from further inheriting by using the "Sealed" keyword. For instance below is a simple sample code where we have a class called as "Human" which is further inherited to create a "Male" or "Female" class.
Now the below code is great but we do not anyone to further inherit from "Male" or "Female" class. In simple words "Male" and "Female" are the last legs in this inheritance hierarchy. This can be done by using the "Sealed" keyword.
If anyone tries to inherit the sealed classes he will end with the below error "cannot derive from sealed type".
Also see following .NET interview questions video on inheritance and Use of Virtual Keyword: -