Page 53 - General and Inorganic Chemistry for Advanced Secondary Schools Students Book Form Five and Six

Biology for Secondary Schools

the slide. This step is optional but Question
can enhance visibility. Based on your observation, describe
6. Gently, cover the specimen with the structure of the root hair.
a coverslip. Gently, press down
FOR ONLINE READING ONLY
on the coverslip to remove any Guard cells
air bubbles and ensure the sample Guard cells surround the stomata.
is adequately flattened. They control the opening and closing
7. Place the prepared slide on the of stomata (singular is stoma) of the

microscope stage. Observe the leaf. The inner walls of guard cells
slide starting with the lowest are thicker than the outer walls. This
magnification power and then makes them expand irregularly. When
adjust the focus knobs to bring the guard cells expand, the stoma

the root hair into focus. opens. When they contract, the stoma
8. Carefully, observe the root hairs closes. Stomata are tiny pores used for
under the microscope, and take gaseous exchange and loss of excess
note of what you have observed. water. Figure 3.14 shows the structure

of a guard cell.

Epidermal cell

Guard cell

Thick inner wall
Stomatal pore
Nucleus

Thin outer wall

Figure 3.14: Structure of a guard cell showing stoma

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