NEET AIPMT SOLVED PAPER SCREENING 2008

  • question_answer
    The \[{{C}_{4}}\]-plants are photosynthetically more efficient than \[{{C}_{3}}\]-plants because

    A) the \[C{{O}_{2}}\]compensation point is more

    B) \[C{{O}_{2}}\] generated during photorespiration is trapped and recycled through- PEP carboxylase

    C) the \[C{{O}_{2}}\]efflux is not prevented

    D) they have more chloroplasts

    Correct Answer: D

    Solution :

    \[{{\text{C}}_{\text{4}}}\text{-}\]plants show Kranz anatomy. In the leaves of \[{{\text{C}}_{\text{4}}}\text{-}\]plants, the vascular bundles are surrounded by bundle sheath of parenchymatous cells, which in turn are surrounded by mesophyll cells. Chloroplasts in bundle sheath cells are larger and always contain grana whereas chloroplasts in mesophyll cells are smaller. The \[{{\text{C}}_{\text{4}}}\text{-}\]plants are photosynthetically more efficient than \[{{\text{C}}_{3}}\text{-}\]plants because they have more chloroplasts. Photorespiration takes place only in \[{{\text{C}}_{3}}\text{-}\]plants. It occurs in chlorophyllous tissue. At high temperature and high oxygen concentration the affinity of RuBP carboxylase for \[C{{O}_{2}}\]decrease and for \[C{{O}_{2}}\] increases. Photosynthesis takes \[C{{O}_{3}}\]and release \[{{O}_{2}}\], while respiration utilizes \[{{O}_{2}}\] and release \[C{{O}_{2}}\]. If the light factor is saturating, there will be certain concentration of \[C{{O}_{3}}\]in the atmosphere at which the rate of photosynthesis will be equal to rate of respiration. This is called carbon dioxide compensation point. \[{{\text{C}}_{\text{4}}}\text{-}\]plants have very low \[C{{O}_{3}}\] compensation point.


You need to login to perform this action.
You will be redirected in 3 sec spinner