During chemosynthesis, bacteria use the energy stored in chemical bonds of either hydrogen sulfide or hydrogen gas in order to produce glucose from dissolved carbon dioxide and water. The chemical reaction for the utilization of hydrogen sulfide in chemosynthesis is shown below. The organisms which perform chemosynthesis are called chemotrophs.
Chemoorganotrophs and chemolithotrophs are the two categories of chemotrophs. Chemolithotrophs use electrons from inorganic chemical sources like hydrogen sulfide, ammonium ions, ferrous ions and elemental sulfur.
Acidithiobacillus ferrooxidans which is an iron bacteria, Nitrosomonas which is a nitrosifying bacteria, Nitrobactor which is a nitrifying bacteria, sulfur oxidizing proteobacteria, aquificaeles and methanogenic archaea are the examples chemolithotrophs. Photosynthesis is the process in which the green plants and algae synthesize glucose form carbon dioxide and water by using sunlight as the source of energy. The pigment chlorophyll is involved in this process. In plants, photosynthesis occurs in specialized plastids called chloroplasts.
Higher plants consist of leaves, containing more chlorophyll in order to carry out the photosynthesis efficiently. Figure 2: Photosynthesizing leaves. Two categories of photosynthesis are found: oxygenic photosynthesis and anoxygenic photosynthesis. Oxygenic photosynthesis occurs in cyanobacteria, algae, and plants, whereas anoxygenic photosynthesis occurs in purple sulfur bacteria and green sulfur bacteria. During oxygenic photosynthesis, the electrons are transferred from water to carbon dioxide.
Thereby, water is oxidized and carbon dioxide is reduced, producing glucose. Hence, the electron donor in oxygenic photosynthesis is water. Oxygen gas is a by-product of oxygenic photosynthesis. In contrast, anoxygenic photosynthesis does not produce oxygen as a by-product.
The electron donor is variable and it can be hydrogen sulfide. The chemical reactions of both oxygenic and anoxygenic photosynthesis are shown below. The organisms which perform photosynthesis are called phototrophs. Photoautotrophs and photoheterotrophs are the two categories of phototrophs. The carbon source of photoautotrophs is carbon dioxide whereas the carbon source of photoheterotrophs is organic carbon.
Green plants, cyanobacteria, and algae are examples of photoautotrophs and some bacteria like Rhodobactor are examples for photoheterotrophs. As the names suggest, photo means sunlight and chemo means chemical. Hence, sunlight provides energy to photosynthesis, while the chemical energy of inorganic compounds provides energy to chemosynthesis. Overview and Key Difference 2. What is Photosynthesis 3. What is Chemosynthesis 4. Similarities Between Photosynthesis and Chemosynthesis 5.
Photosynthesis is a metabolic process by which photoautotrophs convert solar energy into chemical energy in organic compounds such as carbohydrates using carbon dioxide and water as raw materials in the presence of chlorophyll. There are two main processes in photosynthesis; light reaction and dark reaction. The light reaction takes place in the thylakoid membrane. In the light reaction, pigment molecules absorb light energy and transfer to P chlorophyll molecules in the reaction centre of photosystem II.
Once P absorbs energy, its electrons obtain high energy and become boosted. Primary electron acceptors pick up these high energy electrons and pass via a series of carrier molecules like cytochrome and finally pass to photosystem I. When electrons go through the carrier molecules, at each step, energy is released, and the released energy is stored in the form of ATP.
It is the process called photophosphorylation. At the same time, water molecules split by the light energy into O 2, and it is the process called photolysis of water. When four water molecules split, it produces 2 oxygen molecules, 4 protons and 4 electrons.
The produced electrons from photolysis, replace the lost electrons of PS II. Eventually, the produced oxygen releases into the atmosphere. Afterwards, when PS I obtain energy, its electrons also excite into high energy levels. Our knowledge of chemosynthetic communities is relatively new, brought to light by ocean exploration when humans first observed a vent on the deep ocean floor in and found a thriving community where there was no light. Since then, chemosynthetic bacterial communities have been found in hot springs on land and on the seafloor around hydrothermal vents, cold seeps, whale carcasses, and sunken ships.
No one had ever thought to look for them, but these communities were there all along. Continental Margin. Home Ocean Exploration Facts What is the difference between photosynthesis and chemosynthesis? What is the difference between photosynthesis and chemosynthesis?
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