Page 54 - General and Inorganic Chemistry for Advanced Secondary Schools Students Book Form Five and Six

Biology for Secondary Schools

Xylem vessels Question
Xylem vessels are made up of hollow What have you learned from the
dead cells with walls made up of lignin. simulations?
Lignin is a tough rigid material that
FOR ONLINE READING ONLY
makes up the wall of xylem vessels. Activity 3.6: Observing xylem in plant
The cells are connected to form xylem stems
vessels. These vessels transport water
and minerals from the root to the leaves. Materials: Fresh herbaceous plant stem,
They also provide support to the plant. microscope, microscope slide, coverslip,

Figure 3.15 shows the structure of water, dropper or pipette, sharp knife,
notebook, and a pen or pencil.
xylem vessels.
Procedure

1. Select a fresh herbaceous plant with
Walls a thin stem. Herbaceous plants are
non-woody plants with soft stems
that are easier to work on.
2. Carefully, cut a thin cross-section
Lumen
of the stem using a sharp knife. The
cross-section should be about 1-2
mm thick.

Figure 3.15: Structure of xylem vessels 3. Place the cross-section of the stem
on a clean glass slide.

Activity 3.5: Observing cell structure 4. Add a few drops of water to the
and differentiation in plants cross-section to keep it moist and
prevent it from drying out.
Materials: ICT tools, notebook, and 5. Carefully, place a coverslip over the
pen or pencil cross-section, ensuring it covers the
entire area of the specimen.
Procedure: 6. Gently, press down on the coverslip
1. Visit reliable online sources and to remove any air bubbles and
select the appropriate simulations/ ensure the slide is well-prepared

video that describe cell structure and for observation.
differentiation in plants. 7. Place the prepared slide on the
2. Use the selected simulations/video stage of the microscope.
to learn the concept of cell structure 8. Start with the lowest magnification
and differentiation in plants. power and adjust the focus knobs

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