Question
Question: Organisms are able to capture free energy from small inorganic molecules through a process called ch...
Organisms are able to capture free energy from small inorganic molecules through a process called chemosynthesis. These inorganic elements may include
A. Water
B. Sulphur
C. Carbon dioxide
D. Hydrogen
Solution
Inorganic compounds are simple molecules that usually consist of one or two different elements. In Chemosynthesis to produce food some organisms use chemical energy instead of light energy. They are able to survive in harsh and extreme conditions.
Complete answer:
Chemosynthetic organisms capture free energy from small inorganic molecules which are present in the environment and this process occurs in the absence of oxygen. Chemosynthesis is defined as the production of organic compounds and nutrients, by oxidation of inorganic molecules and it uses some energy. Some organisms participate in the precipitation and breakdown of minerals, for example, sulphide oxidizing microbes. The energy stored in chemical bonds of hydrogen sulphide and methane to make glucose from water and carbon dioxide which gets dissolved in seawater. Examples are hydrogen gas, hydrogen sulphide, nitrogen, methane, sulphur.
-Nitrogen bacteria – they are divided into three groups nitrifying bacteria, denitrifying bacteria, and nitrogen-fixing bacteria.
-Methane bacteria/methanobacteria: methane is the source of energy for chemosynthesis.
-Sulfur bacteria, for example – Paracoccus. Inorganic sulphur will be stored and they are used when required in some organisms the stored sulphur is used. Paracoccus bacteria oxidize sulphur compounds like hydrogen sulphide (sulphides), thiosulfates, and inorganic sulphur, etc. The oxidation process takes place in several stages, depending on organisms or type of sulphur used. The inorganic elements may include sulphur sulphide.
Hence, the correct answer is Option B
Note: In oceans and inland waters it is called dark carbon fixation i.e. formation of organic carbon from carbon dioxide in the dark. Chemosynthetic reactions are done in the presence of prokaryotic microorganisms.