What is light-harvesting complex II?

Photosystem II (PSII) is a multisubunit pigment–protein complex located in the thylakoid membrane of cyanobacteria, algae and higher plants. It captures and converts light into chemical energy, which is used to oxidize water and reduce plastoquinone in the light reactions of photosynthesis [1], [2].

What does a light-harvesting complex do?

Light-harvesting complexes are the entry gate of photosynthesis, and determine how much sunlight can be collected and transferred into the photosynthetic systems.

What are the 2 types of photosystem?

There are two types of photosystems in cyanobacteria, algae and higher plants, called photosystem I (PSI, plastocyanin-ferredoxin oxidoreductase) and photosystem II (PSII, water-plastoquinone oxidoreductase), both of which are multisubunit membrane complexes.

Does photosystem 2 use an electron transport chain?

In the photosystem II (PSII) reaction center, energy from sunlight is used to extract electrons from water. The electron transport chain moves protons across the thylakoid membrane into the lumen. At the same time, splitting of water adds protons to the lumen, and reduction of NADPH removes protons from the stroma.

How are light harvesting complexes related to photosystems?

Light harvesting complexes associate with photosystems. This is very useful because the photosystems, PS1 and PSII, just use wave length 680 and 700 nm.

Why are photosystems not in the electron transport chain?

Photosystem I and II don’t align with the route electrons take through the transport chain because they weren’t discovered in that order. Photosystem I was discovered first. Later, photosystem II was discovered and found to be earlier in the electron transport chain.

How is NADPH used in the electron transport chain?

Chlorophyll, which is present in the photosystems, soaks up light energy. The energized electrons are then used to make NADPH. The electron transport chain is a series of molecules that accept or donate electrons easily. By moving step-by-step through these, electrons are moved in a specific direction across a membrane.

How are electrons extracted from water in a photosystem?

In the photosystem II (PSII) reaction center, energy from sunlight is used to extract electrons from water. The electrons travel through the chloroplast electron transport chain to photosystem I (PSI), which reduces NADP+ to NADPH.