Question

describe how factors of haemoglobin ( temperature, ph, number of oxygen molecules bound ) can affect the 3D shape of haemoglobin

Answer 1

That's a very large question. A few very sketchy answers:

(1) If the temperature is high enough, or the pH far enough from neutrality, then the Hb protein will denature, meaning it will unfold from its compact shape to form the shape of a loose coil.

(2) I don't think the number of O2 molecules bound to the Hb materially changes its overall shape -- that is, I don't think it's one of those proteins that undergo a significant conformational shift on ligan binding -- but I do know that the four separate domains of the Hb must "rock" apart in order for O2 to find its way to the central heme group. The channel in is closed in the normal conformation, and a certain kind of wiggle is necessary for it to open.

A lot of work has been done on the relationship between the conformational dynamics of Hb and O2 uptake, but this is pretty advanced stuff -- PhD in chemical physics kind of stuff, for the most part.