question_answer 9)

 Give comparison between the following (i) C3 and C4-pathways (ii) Cyclic and non-cyclic photophosphorylation (iii) Anatomy of leaf in C3 and C4-plants  

Answer:

Answer (i) Comparison between C3 and C4-pathways  

S.N.	Pathway	Pathway
1.     2.       3.       4.       5.	The primary acceptor of CO2 is RuBP, a 5 carbon compound.   It operated under low concentration of CO2 in mesophyll cells.     CO2 once fixed is not released back.   Fixation of one molecule of CO2 needs 3ATP and 2 NADPH2 molecules. It requires 18 ATP for the synthesis of one molecule of glucose.   cycle operates in all category of plants.	The primary acceptor of CO2 is PEP, a 3 carbon compound.   It can operate under very low Co2 Concentration in mesophyll cells.   CO2 once fixed is released back in bundle sheath cells.   pathway requires 30 ATP for the synthesis of one molecules of glucose.     It operates in only plants.

  (ii)       Comparison between Cyclic and Non-Cyclic Photophosphorylation  

S.N.	Cyclic Photophosphorylation	Non-cyclic photophosphorylation
1.   2.   3.   4.   5.   6.	It occurs in photosystem  in stromal or intergranal thylakoids It is not connected to photolysis of water so no oxygen is evolved, It is activated by light of 700 nm wavelength, It generates ATP only there is no formation of NADPH2. Chlorophyll does not receive any electrons from donor, The system does not take part In photosynthesis expect in bacteria, plants.	It is carried out by both PS-I and PS-II in the granal thylakoids. It is connected with photolysis of water, so oxygen is evolved in it. It occurs in 680 nm as well as 700 nm wavelength. It produces both ATP as well as NADPH2 The source of electrons is photolysis of water. This system is connected with CO2 fixation and is dominant in green

(iii)      Comparison between Anatomy of Leaf in C3 andPlants  

S.N	C3 Leaf Anatomy	C4 Leaf Anatomy
1.     2.       3.	Only one type of chloroplast is present,  Less efficient in photosynthesis than C4 leavens.     Only mesophyll cells carryout photosynthesis,	Kranz anatony, i.e., two types of cell, each with its own type of. chloroplast  is present.   More efficient in photosynthesis than C3 leaves.   Both mesophyll cells and bundle sheath cells carryout photosynthesis.