Question

3b. Describe the versatility of the glucose phosphate molecule.

3b. How do plants utilize this molecule?

4a. How are C4 (C-4) and CAM plants similar? 5 points

4b. How are C4 (C-4) and CAM plants different?

Answer 1

3a and b. Glucose phosphate is a versatile molecule as it occupies a prominent position in cellular chemistry. The molecule has many fates and it is reported to be utilized in major metabolic pathways of cell eg.glycolysis and pentose phosphate pathway. The glucose phosphate molecules can also be converted to storage molecules.

An increased concentration of G6P is capable of stimulating G6P dehydrogenase which in turn helps to initiate the glucose-6-phosphate shunt which is an alternative pathway around the Calvin-Benson cycle. Carbon is reduced in the Calvin cycle with the aid of gluconeogenic reactions, and the non-oxidative branch of the pentose phosphate pathway(PPP). The NADPH produced in PPP is utilized in the process of photosynthesis in plants which converts light energy to chemical energy. The NADPH produced by glucose phosphate molecules is also utilized for plant development and stress response.

4a and b

Features	CAM plants	C4 plants
Difference
Plant type	Xerophytic	Mesophytic
Kranz anatomy	Absent	Present
Optimum temperature	35oC	30-40oC
Stomata	Close	Open
Dark reaction	12 NADPH and 39 ATP required	12 NADPH and 30 ATP required
Similarity
Initial carbon dioxide acceptor	Phosphoenol pyruvate	Phosphoenol pyruvate
First stable product	Phosphoenol pyruvate	Phosphoenol pyruvate
Reaction center	Mesophyll cells	Apart from mesophyll cells bundle seaths are also involved