Question

The first formed cells on the primordial earth were

• A. Autotrophic
• B. Parasitic
• C. Prokaryotic and heterotrophic
• D. Prokaryotic and autotrophic

Answer 1

The correct option is C Prokaryotic and heterotrophic

According to a chief carbon source, organisms are classified as autotrophs (self-feeder) and heterotrophs (use organic compounds as carbon source). According to the cellular organization, organisms are classified as prokaryotic (pro=primitive + karyon= nucleus; primitive nucleus without any nuclear membrane) and eukaryotic (Eu = true + karyon= nucleus; true nucleus with well defined nuclear membrane). The first life form, bacteria like a prokaryotic cell, originated from protocell in the Archaeozoic era (3800 million yrs ago, the era of the dawn of life). The first life forms were free anaerobic chemoheterotrophs that used the organic component as a source of energy and carbon. The first life forms were not self feeders but were dependent on the available carbon sources and were free living, not a parasite. Due to the limited supply of organic compounds, organisms evolved photosystem to capture sunlight to be used as a source of energy thereby leading to the origin of photoautotrophs. Thus, the correct answer is option C.