Which step in photosynthesis does not need light?
Carbon dioxide and hydrogen combine to make glucose.
Water splits into hydrogen and oxygen,
Chlorophyll absorbs energy.
Oxygen is released
The step in photosynthesis that does not need light is water splitting into hydrogen and oxygen.
The step in photosynthesis that does not require light is the splitting of water into hydrogen and oxygen.
The step in photosynthesis that does not require light is the splitting of water into hydrogen and oxygen. This process is called photolysis or the light-independent reactions.
To understand why this step does not need light, we need to break down the overall process of photosynthesis. Photosynthesis is divided into two main stages: the light-dependent reactions and the light-independent reactions (also known as the Calvin cycle).
In the light-dependent reactions, which occur in the thylakoid membranes of chloroplasts, light energy is absorbed by chlorophyll and other pigments. This absorbed energy is used to split water molecules, releasing electrons, hydrogen ions (H+), and oxygen gas (O2). The released oxygen is a byproduct and is released into the atmosphere.
After the light-dependent reactions, the light-independent reactions, or the Calvin cycle, take place in the stroma of chloroplasts. In this stage, the energy captured from light is used to convert carbon dioxide (CO2) into glucose (C6H12O6). This is where carbon dioxide and hydrogen combine to form glucose, a sugar molecule that serves as an energy source for the plant.
The light-dependent reactions require light because the absorption of light energy by chlorophyll is essential to drive the process. However, the light-independent reactions do not directly require light. Instead, they rely on the energy captured and stored from the light-dependent reactions in the form of ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate).
Therefore, the splitting of water into hydrogen and oxygen, a step that occurs in the light-dependent reactions, does not need light to proceed.