Question

psi, psii, the etc, and atp synthase are all located in the membranes of these flattened sacs, and are oriented in a way that results in high proton concentrations inside the sacs. a similar thing happens inside mitochondria, which also contain flattened sacs whose membranes contain the etc and atp synthase. which statement is the most logical explanation for the observation that chloroplasts have such an extensive system of internal membranes? the extensive membranes provide an extensive storage area for vesicles used in the endomembrane system and for membrane phospholipids manufactured in the endomembrane system, so they can be reused or distributed to other organelles or the cell membrane itself at a later time. the extensive membranes provide a large surface area for many copies of the photosynthetic machinery (psii, psi, the etc, and atp synthase) to reside, meaning that a lot of atp and nadph production can occur in a small space. plants dont have mitochondria, but instead have chloroplasts to produce energy instead. the flattened sacs in chloroplasts are evolutionary artifacts left over from when plants first evolved. incorrect chloroplasts are where photosynthesis occurs, and do not function as a storage depot for vesicles, phospholipids, or other structures.

Explanation:

The first option is incorrect because chloroplasts are for photosynthesis, not vesicle or phospholipid storage. The third option is wrong as plants do have mitochondria. The second option is correct. Chloroplasts' internal membranes (like thylakoid membranes) provide a large surface area. This allows many copies of photosynthetic machinery (PSII, PSI, ETC, ATP synthase) to be present. As a result, a lot of ATP and NADPH (products of the light - dependent reactions of photosynthesis) can be produced in a relatively small space.

Answer:

The extensive membranes provide a large surface area for many copies of the photosynthetic machinery (PSII, PSI, the ETC, and ATP synthase) to reside, meaning that a lot of ATP and NADPH production can occur in a small space.