Respiration requires O2. How did the first cells on the earth manage to survive in an atmosphere that lacked O2?

In aerobic respiration first CO2 is liberated during

In spite of lack of free oxygen in primitive atomosphere of the earth how present atmosphere contain free oxygen?

Cellular respiration is the oxidation of foodstuffs for the production of energy. During aerobic respiration, complete oxidation of glucose takes place.Contradictor to this, glucose is incompletely oxidized durin anaerobic respiration . Many microbesare capacble of surviving anaerobically in environments that lack oxygen. Anaerobic respiration occurs via two steps,namely glycolysis and fermentation. The pyruvic acid formed during glycolysis is converted to organic acids or alcohols during anaerobic process. higher animals and plants, or seeds submerged in soil under water are capable ofperforming anaerobic respiration, when the oxygen levels are depleted .Even body cells like erythrocytes and mscle cells perform anaerobic respiration. How does anaerobic respiration occur in yeast?

Cellular respiration is the oxidation of foodstuffs for the production of energy. During aerobic respiration, complete oxidation of glucose takes place.Contradictor to this, glucose is incompletely oxidized durin anaerobic respiration . Many microbesare capacble of surviving anaerobically in environments that lack oxygen. Anaerobic respiration occurs via two steps,namely glycolysis and fermentation. The pyruvic acid formed during glycolysis is converted to organic acids or alcohols during anaerobic process. higher animals and plants, or seeds submerged in soil under water are capable of performing anaerobic respiration, when the oxygen levels are depleted .Even body cells like erythrocytes and mscle cells perform anaerobic respiration. Considering that only glycolysis is generating energy currency , how many ATP would be formed during anaerobic respiration?

In H_(2)-O_(2) fuel cell, the reaction occurring at cathode is

Taking into consideration the relationship in the first pair, complete the second pair. Or complete the following: 2H_2+O_2rarr2H_2O: Combination reaction :: 2HgOrarr2Hg+O_2 : .......

Mark the incorrect statement in context to O_2 binding to Hb

Roots obtain oxygen from air in the soil for respiration. In the absence or deficiency of O_2 root growth is restricted or completely stopped. How do the plants growing in marsh lands or swamps obtain their O_2 required for root respiration?

Fish generally needs O_2 concentration in water atleast 3.8 mg/L for survival. What partial pressur of O_2 above the water is needed for the survival of fish? Give te solubility of O_2 in water at 0^@ and 1 atm partial pressure is 2.2xx10^(-3) mol/L

The bond order in O_2 is