Question

why, in the same cell, would you have differently shaped mitochondria?

Answer 1

The Mitochondria is a double layered membrane structure, imagine it is a balloon, we can get different shapes from it depending on how it is pulled and stretched. In the cell there is a complex 'wire' system of proteins and nano tubes that hold the organelles in space. It is also pathways for the organelles to move on if needed.
These networks pull organelles along, this pull can cause distortion on the shape as it is pulled, also the overall shape of mitochondria is unimportant for the most part, in the energy production for the cell. It is the internal structure that has the main function, thus its shape, its wavy formation, allows more surface area for energy production

Answer 2

ok thanks! but im being asked this question in an a level biology paper and it provides me with a diagram with both a circular and elongated shape of mitachondria - is this the kind of answer i'd right - that its because of the double layered membrane? thanks

Answer 3

I dont think its the membrane. I dont have the answer though my best guess is the would be the fibers its attached to.
Maybe it has something to do with the inner membrane when undergoing energy production, have a look online is your best bet