fototransduktsioon

Fototransduktsioon is the process by which light energy is converted into electrical signals in biological systems. This remarkable phenomenon is fundamental to vision in animals and photosynthesis in plants and certain microorganisms.

In the realm of vision, fototransduktsioon occurs within specialized photoreceptor cells in the eye, namely rods and cones. When a photon of light strikes a molecule called a photopigment (such as rhodopsin in rods or photopsins in cones), it induces a conformational change. This change initiates a biochemical cascade that ultimately leads to a change in the electrical potential of the photoreceptor cell. This electrical signal is then transmitted through the nervous system to the brain, where it is interpreted as visual information.

In photosynthesis, fototransduktsioon takes place in chloroplasts. Light energy is captured by pigment molecules like chlorophyll. This energy is used to drive the synthesis of ATP and NADPH, energy-carrying molecules, and to split water molecules, releasing oxygen. These products are then utilized in subsequent biochemical reactions to convert carbon dioxide into sugars, the primary source of energy for the organism. Fototransduktsioon is thus the crucial first step in harnessing light energy for life.