Final answer:
Chlorophyll a's primary function in photosynthesis is to absorb light and energize electrons, which are then used to drive the reactions that produce ATP and NADPH. These energy carriers are crucial for the photosynthetic fixation of carbon dioxide into glucose.
Step-by-step explanation:
The primary function of chlorophyll a in photosynthesis is to absorb light energy and facilitate the photochemical process in photosystems. This pigment molecule specifically absorbs violet-blue and red light, which it uses to get excited and lose an electron to the electron transport chain.
This is a critical step in photosynthesis, as it leads to the generation of chemical energy in the form of ATP and NADPH, which is then used to convert carbon dioxide into glucose. During the light reactions, chlorophyll a molecules in the photosystems are excited and pass their absorbed energy to a primary electron acceptor.
This energy is then used to excite electrons that come from the splitting of water molecules in photosystem II or from the electron transport chain in photosystem I. The splitting of water also has the important byproduct of releasing oxygen as a waste product.