Question

The purpose of the light-dependent reactions of photosynthesis is to __________.

create ATP from NADPH
absorb light energy and use it for ATP and NADPH synthesis
create glucose from carbon dioxide and water
absorb light energy and use it to catabolize glucose

Answer 1

The light-dependent reactions of photosynthesis absorb sunlight to produce ATP and NADPH, which are used in the Calvin cycle to create glucose. This involves the conversion of light energy into chemical energy through photosystems and an electron transport chain.

Step-by-step explanation:

The purpose of the light-dependent reactions of photosynthesis is to absorb light energy and use it for ATP and NADPH synthesis. These reactions take place in the thylakoid membranes of the chloroplasts where sunlight is absorbed by pigments in the photosystems. The light energy is then converted into chemical energy in the form of ATP and NADPH, which are essential for the subsequent Calvin cycle, where glucose is synthesized from carbon dioxide and water. In the light-dependent reactions, photosystem II absorbs energy to start the process, resulting in the transfer of electrons through an electron transport chain, which pumps protons into the thylakoid space, creating a proton gradient. This gradient powers ATP synthase to produce ATP. A second photon is absorbed by photosystem I, leading to the formation of NADPH. Both ATP and NADPH are then utilized in the light-independent reactions to fix CO₂ into organic sugar molecules.