Question

What is the purpose of the cristae in the mitochondria and what structure provides the same role in the chloroplast?

Answer 1

Cristae provide an increase in the surface area of the inner membrane of the mitochondria, allowing a greater space for performing the processes that happen across this membrane, resulting in faster production of ATP.

Grana provides the same role as cristae in the chloroplast

A stack of thykloid forms a group of coiled structures called a granum (plural - grana). The stacked and coiled shape of the grana provides the chloroplast a high SA:V (surface area to volume ratio). The efficiency of light-dependent reactions increase with the increase in the surface area, resulting in more NADPH and ATP production .