8.
layer is where light is absorbed in photosynthesis.
In photosynthesis, light is absorbed by pigments called chlorophyll, which are located in the thylakoid membranes of chloroplasts. The thylakoid membranes are organized into stacks called grana, and each stack is made up of multiple thylakoids. The thylakoids contain the chlorophyll pigments that capture light energy and convert it into chemical energy during the process of photosynthesis.
To understand which layer specifically in the thylakoid membrane absorbs light, we need to take a closer look at the organization of the thylakoid structure. Within each thylakoid, there are multiple protein complexes called photosystems. The two main types of photosystems are photosystem I (PSI) and photosystem II (PSII).
PSII is responsible for the absorption of light energy and the subsequent oxidation of water molecules, producing oxygen as a byproduct. PSI, on the other hand, uses the energy transferred from PSII to drive the production of ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate), which are essential for the later stages of photosynthesis.
So, specifically, PSII within the thylakoid membrane layer of chloroplasts is where the absorption of light occurs during photosynthesis.