PHOTOHETEROTROPH Meaning and
Definition
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A photoheterotroph is a microorganism that obtains its energy from sunlight (or other forms of light) but also requires organic compounds as a carbon source to sustain its growth and metabolism. This term is typically used in the field of microbiology to describe certain bacteria that possess the capability of both photosynthesis and heterotrophy.
Unlike photoautotrophs, which can synthesize their own organic compounds using light energy through photosynthesis, photoheterotrophs lack the ability to produce all their cellular requirements solely from inorganic sources. Instead, they rely on the extracellular organic molecules present in their environment. These organic compounds can be derived from the remains of dead organisms or secretions of living ones.
Photoheterotrophs can employ different mechanisms to acquire their carbon sources, such as through the utilization of organic molecules released by other organisms or by engulfing organic particles. They utilize light as an additional energy source, allowing them to experience growth and sustain metabolic activities in environments where sunlight is available.
Examples of photoheterotrophs include certain species of bacteria, such as Rhodospirillum, Rhodobacter, and Chloroflexus. These organisms possess photosynthetic pigments that enable them to harvest light energy, which is then coupled with the uptake and utilization of organic compounds for carbon and nutrient requirements.
In summary, photoheterotrophs are microorganisms that have the dual ability to utilize light energy, but still necessitate organic compounds for their carbon and energy needs.
Etymology of PHOTOHETEROTROPH
The word "photoheterotroph" is derived from Greek roots.
The Greek word "phōtós" (φωτός) means "light", and "héteros" (ἕτερος) means "other" or "different". These two parts together form "photohetero-", which refers to an organism that obtains its energy from light.
The second part of the word, "troph", comes from the Greek word "trophia" (τροφία), which means "nourishment" or "feeding". This element in the word signifies that the organism acquires its nutrients or sustenance from external sources.
So, combining both elements, "photoheterotroph" refers to an organism that uses light as a source of energy, but relies on organic compounds from other sources for its nutrition.
