Leaf Structure and Function

Free sample questions

Leaf Structure and Function — sample Biology questions with answers

1. Question 1

   Which tissue in the leaf is primarily responsible for photosynthesis?

   • AEpidermis
   • BMesophyll
   • CXylem
   • DPhloem

   Answer: B. Mesophyll

   Mesophyll contains many chloroplasts that carry out photosynthesis. The epidermis usually lacks chloroplasts, while xylem and phloem are involved in transport.

2. Question 2

   The leaf structure that controls water loss through transpiration is

   • ACuticle
   • BStoma
   • CEpidermis
   • DMesophyll

   Answer: B. Stoma

   Stomata are pores controlled by guard cells to regulate transpiration rate. The cuticle reduces transpiration but does not actively control it.

3. Question 3

   Which gas enters the leaf during photosynthesis?

   • A${\text{O}}_2$
   • B${\text{CO}}_2$
   • C${\text{N}}_2$
   • D${\text{H}}_2$

   Answer: B. $\text{CO}_2$

   Carbon dioxide (${\text{CO}}_2$) is required for the Calvin cycle in photosynthesis. Oxygen (${\text{O}}_2$) is a product, not a reactant.

4. Question 4

   The waxy layer on the upper surface of a leaf is called

   • AEpidermis
   • BCuticle
   • CStoma
   • DPalisade mesophyll

   Answer: B. Cuticle

   The cuticle is a waxy layer covering the epidermis to reduce water loss. It is not a cellular tissue.

5. Question 5

   Guard cells function to

   • AAbsorb sunlight
   • BControl the opening and closing of stomata
   • CTransport water to the leaf
   • DProduce glucose

   Answer: B. Control the opening and closing of stomata

   Guard cells change shape due to turgor pressure to open or close stomata, regulating gas exchange and transpiration.