The Living World Question 7
7. Organisms which obtain energy by the oxidation of reduced inorganic compounds are called
(a) photoautotrophs
(b) chemoautotrophs
(c) saprozoic
(d) coproheterotrophs
Show Answer
Answer : b
Hints & Solutions
(b) The organisms obtaining energy by chemical reactions independent of light are called chemotrophs. When the reductants obtained from the environment are in inorganic form then organisms are called chemoautotrophs. If they are organic, then the organisms are chemoheterotrophs. Photoautotrophs make their food by photosynthesis using energy from the sun. Saprozoic organisms obtain food from dead and decaying matter. Chemoheterotrophs can be chemolithoheterotrophs, utilizing inorganic electron sources such as sulfur, or chemoorganoheterotrophs, utilizing organic electron sources such as carbohydrates, lipids, and proteins. Most animals and fungi are examples of chemoheterotrophs, obtaining most of their energy from $O_2$.
