QUESTION 1 (5) (5) 1.1 Briefly discuss the field of study concerned with the flow of energy through living organisms, and the two basic laws that govern biological energy transformations. 1.2 Describe in perspective the central role of photosynthesis in life on earth. 1.3 "Explain the structure and composition of nitrate reductase, and the role of the enzyme in nitrate assimilation". QUESTION 2 2.1 Discuss the mobilization of starch for use during glycolysis. 2.2 What are the functions of oxidative pentose phosphate pathway? QUESTION 3 (15) [25] (15) (10) [25] The photosynthetic carbon reduction (PCR) cycle is said to be "autocatalytic"; write short notes on the meaning of the above statement and on the autocatalytic properties of the PCR. [10] QUESTION 4 4.1 Discuss the three stages in the formation of symbiotic nitrogen-fixing associations in legumes. (15) 4.2 Describe the basic molecular composition of the flavonoids, their chemical properties and biological function. (10) [25] QUESTION 5 Explain the pathway in C3 plants in which photoassimilates from photosynthesis are re- oxidised eventually resulting in the release of CO2. You should also use a scheme to indicate the reactions as well as the organelles involved in this pathway. [151