Major Events During Photosynthesis:
- Light Absorption:
During photosynthesis, light energy is absorbed by chlorophyll molecules in the chloroplasts of plant cells. This light energy is essential for driving the process of photosynthesis.
- Water Splitting:
The absorbed light energy is used to split water molecules into oxygen, protons, and electrons. This process, known as photolysis, occurs in the thylakoid membranes of the chloroplasts.
- ATP and NADPH Production:
The electrons released from water splitting are used to generate ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate) through a series of reactions known as the light-dependent reactions.
- Carbon Fixation:
In the Calvin cycle, the ATP and NADPH produced during the light-dependent reactions are used to fix carbon dioxide from the atmosphere. This process involves the conversion of carbon dioxide into glucose, a form of stored energy.
- Glucose Production:
The glucose produced through carbon fixation serves as the primary source of energy for the plant and is essential for growth and development. It can be used immediately for cellular respiration or stored as starch for later use.
- Oxygen Release:
As a byproduct of photosynthesis, oxygen is released into the atmosphere. This oxygen is vital for aerobic respiration in plants and animals, as well as for maintaining the balance of gases in the Earth's atmosphere.