Mitochondrial/chloroplast Membranes

Question 1

What membranes are used by/in:
Bacteria
Respiration
Photosynthesis?

Answer 1

Bacteria - cell membrane
Respiration - mitochondria inner membrane
Photosynthesis - thylakoid membranes of the chloroplasts

Question 2

What is the common function of the inner membranes of mitochondria/ chloroplasts/ bacterial cell membrane?

Answer 2

They only let protons through in a highly controlled fashion. Also, the membranes are watertight (sealed membranes) because protons are very small and easily pass through water molecules