cells part 2

1. Biology

2. Cells, tissues, organs and organisms.
Cells of the same kind grouped together form
Tissue.
Tissues of different kinds grouped together form
Organ.
Organs of different kinds grouped together form
Organ system.

3. All organs and organ systems in a living thing form
An organism (the
body of the living
thing)

4. Plants as living organisms
The tissues in the leaf work together and form an organ the leaf.

5. Upper epidermis
Palisade mesophyll
Spongy mesophyll
Lower epidermis
Waxy Cuticle
Stomata
(Singular: stoma)
Xylem tissue

7. 1) Epidermis
• Form the outer covering of the plant.
• They are broad and flat and joined together.

8. 2) Palisade mesophyll
• They are under the upper epidermis.
• The function of this layer is to take
sunlight and make food.

9. 3) Spongy mesophyll
• It is under the palisade layer.
• They are rounder and have gaps
between them.
• Their task is to help bring water to the
leaf for use in making food.

10.  When water evaporates it is replaced by water drawn up in
tube like called xylem tissue.
 It forms much of the mid rib and
veins in the leaf.

11.  They are specialized pairs of cells in the lower epidermis of a
leaf can bend to make an opening through which water
vapour can escape from spongy mesophyll.
 Stomata is the pleural while stoma is the singular.