This is in complete opposition to Hegel’s teachings, which define culture in general terms as the manifestation of the unity of Geist and therefore independent from the mutability of immediate reality. Philosophy, religion, morals and all the other aspects of culture are universals determined on the temporal plane.
In opposition to this, Marx tells us that culture is socially determined and, as such, mutable and susceptible to the changes that affect its context. Cultural production reflects more or less directly this dependence from the dynamics between social relations.
In his preface to A Contribution to Political Economy (1859), Marx condenses the essence of this concept that he calls Historical materialism: “it is not the consciousness of men that determines their existence, but their social existence that determines their consciousness” (http://www.marxists.org/).
All the ideas we have, those through which we interpret the world, the moral and religious values through which we judge it, form a system, that of ideology, a superstructure that is entirely dependent on the structure of society. A change to the latter inevitably brings about a shift in the former.
In return, the superstructure grants the legitimization of the social structure by reinforcing and expressing ideals sympathetic to the dominant class. In this sense, ideology manufactures a false representation of reality. This is, for Marx, the machine of mystification through which the masses are enslaved.