AP BIOLOGY

Detailed explanation-1: -Photosystem I occurs before photosystem II during the light reactions. a collection of pigments that trap solar energy and focus it on reaction centers, releasing high-energy electrons.

Detailed explanation-2: -Photosystem I comes before photosystem II in the noncyclic electron pathway. Photosynthesis and cellular respiration utilize the same chemical pathways but in reverse of each other. Photosynthesis and Only organisms with chloroplasts are capable of photosynthesis.

Detailed explanation-3: -Photosystem II (PSII) is a membrane protein supercomplex that executes the initial reaction of photosynthesis in higher plants, algae, and cyanobacteria. It captures the light from the sun to catalyze a transmembrane charge separation.

Detailed explanation-4: -Photosystem I and photosystem II are the two multi-protein complexes that contain the pigments necessary to harvest photons and use light energy to catalyse the primary photosynthetic endergonic reactions producing high energy compounds.

Detailed explanation-5: -Photosystem II most likely evolved first, because it replaces electrons lost from chlorophyll a with electrons from water. Since photosystem I accepts electrons from photosystem II, it probably evolved after photosystem II.