Page 13 - Focus PT3 2020 Science ( BI Version )

Science PT3 Chapter 2 Cell as the Basic Unit of Life

Epidermal cells Palisade cells
• Epidermal cells are flat and Cuticle layer • Contain lots of Cell wall
have a large vacuole. chloroplasts which Chloroplast
• Coated by a waxy cuticle layer contain chlorophyll.
on top, this reduces water loss. • Absorb sunlight to Vacuole
• Epidermal cells are transparent carry out photosynthesis. Cytoplasm
Form
Form
1 to allow light to penetrate the Nucleus
cell for photosynthesis.
Plant cells
Root hair cells Guard cells A pair of guard cells
• Have a long thin extension, • Kidney-shaped cells.
the root hair which provides Root hair • Two guard cells surround Chloroplast
a large surface area for an opening called stoma. Stoma
absorption of water and • Guard cells help to regulate
nutrients from the soil. gas exchange by opening
and closing the stoma.

Figure 2.14 Various types of specialised cells in plants and their functions

Formation of an Organism

1. Cells in multicellular organisms are 4. Several specialised organs work together
organised to form tissues, organs and to form a system which performs a major
systems which all together form an function.
organism.
5. All the systems combine to make up what
2. Cells of the same structure that carry out a is known as a multicellular organism.
similar function make up a tissue.

3. A group of different tissues that work
together to perform a particular function
forms an organ.

HOTS Challenge
Praktis Formatif 1 1
• Evaluating
Is blood a cell or a tissue? Why?
Human

Digestive system Multicellular
organism
All the systems
Stomach System combine to form
Several organs a multicellular

Epithelial tissue Organ work together to organism.
perform a major
Two or more
types of tissues function.
Epithelial cell Tissue work together to
A group of perform a particular
Cell specialised cells function.
Basic unit of life. with a similar
function. Figure 2.15 Cell organisation in a
multicellular organism

36

02 Fokus Science F1.indd 36 11/19/19 11:41 AM