12 std Chemosynthesis Bio Botany 12th Standard Study Material & audio notes
12th botany neet school

Chemosynthesis

Chemosynthesis

Chemosynthesis

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Chemosynthesis is a process by which certain organisms synthesize carbohydrates by using energy obtained by the oxidation of inorganic substances.

Most of the bacteria obtain their food materials from external sources and they cannot synthesize their food by themselves.

These are called heterotrophic organisms.

Whereas, some bacteria are capable of synthesizing their food either by photosynthesis or chemosynthesis.

Organisms which use sunlight energy for synthesis of food materials are called photosynthetic organisms or photoautotrophs.

Those organisms which use chemical energy for the synthesis of carbon compounds are called chemosynthetic organisms.

There are two groups of chemosynthetic organisms namely, chemosynthetic autotrophs and chemosynthetic heterotrophs.

Chemosynthetic autotrophs

Examples for chemosynthetic autotrophs are Nitrosomonas, Beggiatoa.

Nitrosomonas oxidizes ammonia into nitrite.

The energy liberated during this process is used for the synthesis of carbohydrates.

2NH3 +3O2  → 2NO2 +2H2O + 2H+ + Energy

Beggiatoa oxidises H2S to sulphur and water.

During this, energy is released and used for its growth.

Sulphur is stored as granules inside cell.

H2S + [O] → H2O + S + Energy

Chemosynthetic heterotrophs

Examples for chemosynthetic heterotrophs are fungi, most bacteria, animals and man.

These organisms cannot prepare their food materials, hence they are heterotrophs.

They obtain the energy for growth by chemi- cal reactions ie. by oxidizing the organic compounds.

For example, en- ergy is released when glucose is oxidised in the process of respiration.

Thus, these organisms are chemosynthetic heterotrophs.

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Other links 

Plant tissue culture – origin and techniques


Plant physiology – photosynthesis and its significance


Site of photosynthesis and Mechanism of photosynthesis


Electron transport system and photophosphorylation types


Dark reaction


C3 and C4 pathways


Photorespiration or C2 cycle


Factors affecting photosynthesis


Test tube and funnel experiment, Ganong’s light screen experiment


Mode of nutrition – Autotrophic, Heterotrophic


 

Mechanism of Respiration – Glycolysis


Mechanism of Respiration – Oxidative decarboxylation , Krebs cycle


Mechanism of Respiration – Electron Transport Chain, Energy Yield


Ganong’s respiroscope, Pentose phosphate pathway


Anaerobic respiration, Respiratory quotient, Compensation point, Kuhne’s fermentation tube experiment


Plant growth and Measurement of plant growth


Phytohormones Auxins


Phytohormones Gibberellins


Phytohormones Cytokinin, Ethylene, Abscisic Acid, Growth Inhibitors – Physiological Effects


Photoperiodism and vernalization, Phytochromes and flowering

 

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