Boeing tests its wings to breaking by bending them behind the back of the plane until they are pointed up at ridiculous angles. The kind of force that would break the wings of a modern jetliner would also break the necks of a large number of the passengers.

http://www.youtube.com/watch?v=pe9PVaFGl3o

EDIT: I stand corrected. As pointed out below, that huge deflection doesn't represent neck-breaking forces. But imagining the force of an updraft that can accelerate an airliner upwards at 2G's -- that's still a heck of a lot of power.

Not at all. The A340 limit load factor is something like +2.5 / -1.0g. This is not a condition injurious to seated passengers. It is unrestrained passengers who are injured in turbulence -- but that is due to the passenger/cabin collision, not the initial acceleration. The wings in the video flex a long way under these relatively light load factors because the wings are designed to be only a little bit stronger than they need to be.

Aerobatic airplanes and pilots routinely experience transients to +/-6g with no ill effects.

Cool video. I wonder how much of an engineering/structural difference there is between the heavier 777 and the Airbus A330-200 that crashed.

Both are tested to 150% of their maximum rated load.