Light dependant reaction

In the thylakoids membrane.

Photosystems are large protein-pigment complexes with antennas in the thylakoid membrane. Each photosystem contains many chlorophyll molecules

Reduced NADP and ATP as they are used for the light independent reaction

Photosystems antennas absorb light energy from the sun and transferred to reaction centre. Electrons in chlorophyll within reaction centre become excited and leave the molecule😀 Excited electrons passed through a series of electron carrier proteins embedded in the thylakoid membrane known as the electron transport chain

As electrons pass through the electron transfer chain through each protein they release energy. This is because they reduce the proteins when entering and oxidise them when leaving. This energy is used to pump H+ protons through the thylakoid membrane from the stroma to the thylakoid lumen by active transport. These protons return to the stroma by passing through the enzyme ATP synthase via facilitated diffusion (chemiosis - at every electron carrier electrons move to a LOWER energy level) ATP synthase then catalyses the reaction between ADP + Pi to form ATP. (Photophosphorylation)

Hydrogen ions in the stroma are combined with the co-enzyme NADP. ELECTRONS are also combined with NADP which is why it is reduced 2H+ + 2e- + NADP → NADPH

Light energy is also used to split water molecules in the thylakoids lumen. H2O → 2H+ + 2e- + ½O2

H+ protons are pumped across the thylakoid membrane during ATP production and they also join with NADP to form reduced NADP electrons are passed to the photosystem to replace those lost during photoionisation Oxygen is a waste product and diffuses out of the leaf cell

Photosystems is usually ignored by the mark scheme so use chlorophyll to be more specific