fotoautotrofia

Fotoautotrofia, also known as photoautotrophy, is a metabolic process by which certain organisms synthesize organic compounds—primarily carbohydrates—using light as the primary energy source. This process is fundamental to life on Earth, as it forms the basis of the food chain by enabling the production of organic matter from inorganic substances.

The most well-known example of photoautotrophy is photosynthesis, carried out by plants, algae, and some bacteria. During photosynthesis, organisms absorb light energy through pigments such as chlorophyll, which drives the conversion of carbon dioxide (CO₂) and water (H₂O) into glucose (C₆H₁₂O₆) and oxygen (O₂). This reaction occurs in two main stages: the light-dependent reactions, which capture light energy and produce ATP and NADPH, and the Calvin cycle (light-independent reactions), where ATP and NADPH are used to fix CO₂ into organic molecules.

Photoautotrophs are classified as primary producers because they generate their own food rather than relying on external organic sources. This ability distinguishes them from heterotrophs, which obtain energy by consuming organic matter. Photoautotrophy is particularly important in ecosystems, as it supports the growth of herbivores and, indirectly, carnivores.

Some bacteria, such as cyanobacteria and purple bacteria, also exhibit photoautotrophy, though their photosynthetic pathways may differ slightly from those of plants. For instance, cyanobacteria use water as an electron donor, releasing oxygen as a byproduct, while other bacteria may use alternative compounds like hydrogen sulfide.

The efficiency of photoautotrophy varies among organisms and is influenced by environmental factors such as light intensity, temperature, and nutrient availability. Despite its ecological significance, photoautotrophy remains a complex process that continues to be studied for its potential applications in biotechnology and sustainable energy.