During photochemical reactions of photosynthesis:

$Z$-scheme in the thylakoid membrane of plants is concerned with:

When the two pigment systems absorb light,in what direction does the energy flow between them?

$ATP$ synthesis in chloroplasts and mitochondria is due to a proton gradient across the membrane. Select the correct statements with respect to $ATP$ formation in chloroplasts:
$(a)$ Protons accumulate in the lumen of the thylakoid.
$(b)$ Splitting of water occurs on the inner side of the membrane.
$(c)$ Protons accumulate on the stroma side of the chloroplast.
$(d)$ $NADP$ reductase is located on the stroma side of the membrane.

The first step of photosynthesis is:

$ATP$ formation in photosynthesis is known as