First, watch this, then I'll get to my main point below:
While what eh says about the whole 2012 deal is pretty spot on, he makes a broader point that I think is worth discussing: that scientific literacy doesn't mean simply knowing facts and being able to spout information, it means knowing how to ask the right kinds of questions.
A knowledge of physics and/or astronomy informs you that when someone tells you that some particular cosmic event will occur and cause carnage, ask how often said event occurs as this will allow you to gauge the accuracy of their claim.
A knowledge of biology or chemistry informs you that when someone tells you that a food or medication contains "a toxin", ask how much it contains and at what level the substance is actually toxic (some "known toxins" are also necessary nutrients in low doses, others are natural byproducts of the human body and therefore harmless in low doses [formaldehyde is a good example of this], and every toxic substance has a threshold that it must pass before it actually becomes dangerous).
And so on. It's important to remember that the great advantage of scientific literacy is not that it allows a person to rattle off a list of facts, but that it allows them to make informed decisions and ask the right questions when someone is either trying to scam them or trying to persuade them of a false conclusion.