Carbon Cycle

(i) Make a neat and labelled sketch of nitrogen cycle in nature. (ii) Describe in brief the role of nitrogen fixing bacteria and of lightenng in fixing atmospheric nitrogen. OR (i) Draw a neat labelled sketch of carbon cycle in nature. (ii) What is green house effect? How does carbon dioxide cause global warming in the atmosphere.

Outline salient features of carbon cycling in an ecosystem

The photorespiratory carbon-oxidation cycle involves the interaction of

Why are carbon and nitrogen cycles called gaseous cycles ?

What is meant by the term 'cycles of matter' ? Explain the carbon or nitrogen cycle.

If Q_(1) and Q_(2) are the energies released in the fusion of hydrogen in Carbon-nitrogen cycle and proton-proton cycle respectively then cycle repespectively then

(a) Draw a well labelled nitrogen cycle in nature. (b) Describe one biological and one physical method of conversion of nitrogen to forms like nitrates and nitrities. OR (a) Draw a labelled carbon cycle in nature. (b) Describe briefly two process by which carbon dioxide is returned back to the atmosphere.

Energy is released from stars due to nuclear fusion taking place in two cycles proton-proton cycle and carbon nitrogen cycle. In these cycles four hydrogen nuclei combine to from helium nucleus. In this fusion reaction in addition to energy how many number of nutrinous are released ?

Two molecules of the primary acceptor of carbon dioxide in Calvin cycle undergoes photorespiration. How many glycine molecules will be formed from it ?

The carbon dioxide acceptor in the Calvin cycle is