Question

Given below is a diagrammatic representation of cross-section of a leaf: 

Identify ‘P’ in the given diagram and write down its role in plants. Write down a balanced equation of process of photo-synthesis.

Hint:

Palisade mesophyll = Main photosynthesis site. Photosynthesis: CO$_2$ + H$_2$O → Glucose + O$_2$ (sunlight).

Answer 1

Identification of ‘P’:

In the given cross-section of a leaf, label P indicates the Palisade Mesophyll Cells.

Reason:
– These cells are elongated and arranged vertically just below the upper epidermis.
– They contain a large number of chloroplasts.
– They are the main site of photosynthesis in the leaf.

Role of Palisade Mesophyll in Plants:
– They absorb maximum sunlight because they are located near the upper surface of the leaf.
– They contain numerous chloroplasts that trap light energy.
– They carry out photosynthesis and prepare food for the plant.

---

Balanced Equation of Photosynthesis:

Photosynthesis is the process by which green plants prepare food in the presence of sunlight and chlorophyll. \[ 6CO_2 + 6H_2O \xrightarrow{\text{sunlight, chlorophyll}} C_6H_{12}O_6 + 6O_2 \]

Explanation:
– Carbon dioxide is taken from air.
– Water is absorbed from soil.
– In the presence of sunlight and chlorophyll, glucose is formed.
– Oxygen is released as a by-product.

Conclusion:
‘P’ represents palisade mesophyll cells which are responsible for photosynthesis. The process of photosynthesis converts carbon dioxide and water into glucose and oxygen.