C# version of java’s synchronized keyword?

Does c# have its own version of the java “synchronized” keyword?

I.e. in java it can be specified either to a function, an object or a block of code, like so:

public synchronized void doImportantStuff() {
   // dangerous code goes here.
}

or

public void doImportantStuff() {
   // trivial stuff

   synchronized(someLock) {
      // dangerous code goes here.
   }
}