Question : Respiration requires O_(2) . How did the first cells on the earth manage to survive in an atmosphere that lacked O_(2) ?

Question : Respiration requires O_(2) . How did the first cells on the

1.	Question : Respiration requires O_(2) . How did the first cells on the earth manage to survive in an atmosphere that lacked O_(2) ?
Answer» Solution :`O_(2)`is not ALWAYS required for respiration. Some living organismssurvive in ABSENCE of `O_(2)`by doing anaerobic respiration. The first cell on the earth, like photosyntheticbacteria are PROKARYOTIC type organismson the earth theyobtained energy by BREAK down of inorganicsubstances. e.g. In chemosynthetic bacteria (Sulphur bacteria) chemosynthesisoccurs in following WAY `12 H_(12) S + 6CO_(2) to C_(6) H_(12) O_(6) + 6H_(2) O + 12S darr`