Bioenergetics: Photosynthesis

Photosynthesis: Definition and Importance

Photosynthesis is the process by which green plants, algae, and some types of bacteria absorb sunlight and convert it into chemical energy in the form of glucose.
It is an endothermic reaction, meaning that it requires an input of energy, which comes from the sun.
Plants are producers or autotrophs, meaning that they do not need to consume other organisms to obtain energy.
Photosynthesis is crucial for life on earth because it produces oxygen, a necessary component for cellular respiration.

The general equation for photosynthesis is: 6CO2 + 6H2O + sunlight energy => C6H12O6 + 6O2
This indicates that carbon dioxide and water react in the presence of sunlight to produce glucose and oxygen.

Light-dependent reactions occur in the thylakoid membranes of the chloroplasts. This stage uses energy from sunlight to convert ADP and NADP+ into ATP and NADPH, releasing oxygen in the process.
Light-independent reactions, also known as the Calvin cycle, take place in the stroma of the chloroplasts. During this stage, ATP and NADPH from the light-dependent stage are used to convert carbon dioxide into glucose.
Photosynthesis requires chlorophyll, a pigmented molecule that absorbs light energy and passes it onto other molecules, initiating the photosynthetic process.

The rate of photosynthesis can be affected by several factors, including light intensity, temperature, and the concentration of carbon dioxide.
As light intensity increases, the rate of photosynthesis will increase proportionally until reaching a saturation point.
The process is most efficient at an optimal temperature. Both too low and too high temperatures may negatively affect the rate of photosynthesis.
High concentrations of carbon dioxide stimulate photosynthesis until a maximum rate is reached.