Photosynthesis vs. Chemosynthesis: What's the Difference?

Key Difference

Photosynthesis uses solar energy to produce glucose while chemosynthesis does not require solar energy to produce glucose.

Comparison Chart

Photosynthesis Chemosynthesis
Occurs in Green plants Bacteria
Discoverer Jan Ingenhousz S.N Vinogradskii (1887)
Fuels Water, carbon dioxide and solar energy Inorganic compounds
End products Glucose and oxygen Glucose and oxygen
Uses As fuel for life As fuel for life

What is Photosynthesis?

Ecosystem depends upon the ability of organisms to convert inorganic compounds into food that other organisms use as fuel for their lives. Photosynthesis is a primary food production which is powered by solar energy. Plants and microbes cannot eat food, so they have to make food for themselves. Photosynthesis takes place in plants and some bacteria, where there is sufficient sunlight. This occurs on land, shallow water and sometimes below ice where sunlight can reach. Photosynthetic organisms species and plants convert carbon dioxide and water into sugar and oxygen by using sun light. Following formula is a description of this reaction: CO2 + 6H2O -> C6H12O6 + 6O2 Plants draw water from the soil up through roots. The water is then transferred to the leaves by particular cells of plants called xylem. Plants consume some water when other natural processes occur, and some water is used during the photosynthesis process. Plants have special cells called stomata which open and close on stimulus. Plants take carbon dioxide through the stomata and release oxygen formed during the chemical reaction of photosynthesis. Plants also lose some water during this gas exchange. Chlorophyll is a complex molecule which is present in green plants and absorb light. Any substance which absorbs light is called pigment. Pigments absorb light of a specific wavelength and reflect the rest back. Chlorophyll absorbs all wavelength of light except for green. Because of this reason, grass and leaves of trees look green. When a plant absorbs light energy or carbon dioxide, chlorophyll causes the chemical reaction which turns the light into two different substances; ATP and NADPH. ATP stands for adenosine triphosphate, and NADPH stands for nicotine adenine dinucleotide phosphate. These two substances are both unstable forms of energy which the plant then uses for other reactions. During a chemical reaction, water molecule gets splits and release oxygen into the air.


What is Chemosynthesis?

Chemosynthesis is another process which provides fuel to live on earth. In some environments, primary production of fuel occurs through chemosynthesis (a nutrition characteristic) which runs on chemical energy. Chemosynthesis is a process of use of energy produced by inorganic chemical reactions to produce food.  This process occurs in the heart of deep sea communities, sustaining life in the absolute darkness where the light of the sun does not penetrate. All organisms doing chemosynthesis use the energy released by chemical reactions to make sugar. Different species use different pathways for chemosynthesis. For example, undersea hot springs are the most extensive ecosystem which based on chemosynthesis. At these hydrothermal vents, bacteria oxidize hydrogen sulfide, add carbon dioxide and oxygen and produce water, sulfur, and sugar. Other bacteria produce sugar matter by reducing sulfide or oxidizing methane. Chemosynthetic bacteria are present in hot springs on land and on the seafloor around hydrothermal vents, whale carcasses, cold seeps and sunken ships. Hydrogen bacteria are most numerous group of chemosynthetic bacteria.


Photosynthesis vs. Chemosynthesis

  • Both photosynthesis and chemosynthesis need carbon dioxide as fuel for the process to produce carbohydrates.
  • Both processes result in energy source for the organisms.
  • Photosynthesis occurs only in green plants or in organisms which have chlorophyll while chemosynthesis occurs only in bacteria.
  • Photosynthesis needs sun energy as an essential requirement while chemosynthesis does not need solar energy for the process.
  • Photosynthesis also needs oxygen for the process while chemosynthesis does not need oxygen for the process.
  • Water is used during the process of photosynthesis while water is produced as the end product in chemosynthesis.
  • Photosynthesis provides significant contribution of energy to the total biosphere energy reserve while chemosynthesis shows no such contribution.

Explanatory Video

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