Question

Which of the following structure utilises both oxygen and carbon dioxide?

• A. I, II, III, V, and VI
• B. I, V, and VI
• C. VI
• D. II and III
• E. IV and VI

Answer 1

Answer: (D)

II and III

• The upper (I) and lower (V) epidermis together make dermal tissue of the leaf. Small pores present in the lower epidermis are called stomata (VI) and serve in exchange for respiratory gasses.
• Vascular bundles (IV) are involved in the conduction of food and water. Palisade (II) and spongy (III) mesophyll cells have photosynthetic pigments chlorophyll.
• RUBISCO enzyme is present in these cells that have an affinity for both oxygen and carbon dioxide.
• Fixation of carbon dioxide by RUBISCO leads to the synthesis of sugars while its affinity for oxygen leads to the photorespiratory pathway.
  
  Hence, the correct answer is option D.