The way I see it...
Robyn
If you look at a video on youtube of the B787 testing ...as the 'plane rotates..ahem..takes off from the ground you see the wings BEND.
It is though like a toy with invisible strings: pulls the whole mass, prolly 300 tonnes, pulled up by the wing tips. Do you agree?
Now I make that 150 tonnes per wing. The wing area is more near the "root" where the wing comes out of the fuselage, so there it is really strong. Then at the end where the winglets are, it is delicate and I guess that is why it bends more.
Then we have all the other wing shapes too...like the old Delta wings on our V bombers here in the UK and same as Concorde. I am sure they did bend a little but nothing like we see now with the B787 or the A380 or that huge Antolov Russian transport 'plane.. Do you agree?
Regards