Prokaryotes lack mitochondria and instead create energy molecules (ATP) on the surface of their cell membrane.
A single-celled creature without a nucleus and other membrane-bound organelles is known as a prokaryote.
A prokaryotic cell, such as a bacteria, usually lacks membrane-bound cell organelles.
Biochemical activities such as energy synthesis via the Krebs cycle take place on mesosomes in such cells.
Mesosomes are complicated infoldings of the bacterial plasma membrane that enhance biosynthetic space in a bacterial cell that lacks cell organelles normally.