The plasma membrane as I explained is a biological membrane that separates the interior of all cells from the outside environment. What I meant by this
and it also manufactures biomolecules.
is that the plasma membrane consists of a lipid bilayer with embedded proteins (which can also be called biomolecules) since biomolecules is a loosely used term to describe molecules and ions found in organisms that aid biological processes.
Perhaps I was wrong to say these molecules are produced by the plasma membrane.
Exactly :)