Q15 of 44 Page 79

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

The first cells on the earth managed to survive in an atmosphere that lacked O2 because they were anaerobes ,i.e. they did not require oxygen for respiration and instead survived by the breakdown of other inorganic compounds like H2S etc. They survived without the presence of oxygen.


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13

A process is occurring throughout the day, in ‘X’ organism. Cells are participating in this process. During this process ATP, CO2 and water are evolved. It is not a light dependent process.

a. Name the process.


b. Is it a catabolic or an anabolic process?


c. What could be the raw material of this process?


 14

When a substrate is being metabolized, why does not all the energy that released in one step. It is released in multiple steps. What is the advantage of step-wise release?

 16

It is known that red muscle fibres in animals can work for longer periods of time continuously. How is this possible?

 17

The energy yield in terms of ATP is higher in aerobic respiration than during anaerobic respiration. Explain.