Science 7

2. TheStructures of
Plant and Animal
Cell

3. Introduction
• Cells are the basic units of organisms
– Cells can only be observed under microscope
• Two basic types of cells:
AnimalCell PlantCell

4. The cell as the basic unit of life
• Cell is the smallest unit of living organisms
• Unicellular organisms are made of one cell
only
• The cells of multicellular organisms are
specialized to perform different functions
– e.g. mesophyll cells for photosynthesis
and root hair cells for water absorption

5. mitochondrion
nucleus
glycogen
granule
cell
membrane
cytoplasm
Animalcell
• No cell wall and
chloroplast
• Stores glycogen
granules and oil
droplets in the
cytoplasm
vacuole

6. Organelles
very small size – can only be
observed under electron
microscope
has specific functions
in cytoplasm

7. Endoplasmic
Reticulum
• A.k.a. “ER”
• Connected to nuclear
membrane
• Highway of the cell
• Rough ER: studded with
ribosomes; it makes
proteins
• Smooth ER: no
ribosomes; it makes
lipids

8. Ribosome
• Site of protein
synthesis
• Found attached to
rough ER or floating
free in cytosol
• Produced in a part of
the nucleus called
the nucleolus

9. Golgi
Apparatus
• Looks like a
stack of plates
• Stores,
modifies and
packages
proteins

10. Centriole
• Aids in cell
division
• Usually found only
in animal cells
• Made of
microtubules

11. Cytoskeleton
• STABILIZES the lipid
membrane
SYSTEM of fibers or
NETWORK of protein
filaments
Strengthens, Supports
Stiffen the cell

12. • Cell wall
–Made of cellulose
which forms very thin
fibres
–Strong and rigid
–In plant cells only

13. Lysosome

14. • Cell wall
– Protect and support
the enclosed
substances
(protoplasm)
– Resist entry of excess
water into the cell
– Give shape to the cell

15. • Cell wall
–A dead layer
–Large empty spaces
present between
cellulose fibres
freely permeable

16. • Cell membrane
–Lies immediately
against the cell wall
–Made of protein and
lipid Selectively
permeable

17. • Cell membrane
–A living layer
–Can control the
movement of
materials into and
out of the cell

18. • Cytoplasm
–Contains organelles
and granules :
•e.g. chloroplast
•e.g.mitochondrion

19. • Cytoplasm
–Jelly-like substance
enclosed by cell
membrane
– Provide a medium for
chemical reactions to
take place

20. –Contain the green
pigmentchlorophyll
•To trap light energy,
to make food by
photosynthesis
• Chloroplast

21. • Chloroplast
–Contain starch grains
(products of
photosynthesis)

22. –Rod shape
–For respiration
• Mitochondrion
( mitochondria )

23. – Active cells ( eg.
sperms, liver cells)
have more
mitochondria
• Mitochondrion
( mitochondria )

24. • Vacuole
– large central vacuole
– Surrounded by tonoplast
– Contains cell sap
• a solution of chemicals
(sugars, proteins,
mineral salts, wastes,
pigments)

25. • Nucleus
–Control the normal
activities of the cell
–Bounded by a
nuclearmembrane
–Contains thread-like chromosomes

26. • Nucleus
–Each cell has fixed
number of chromosomes
• Chromosomes carry
genes
–genes control cell characteristics

27. Different kinds of plant cells
Onion Epidermal Cells
Root Hair Cell
root hair
Guard Cells

28. Different kinds of animal cells
white blood cell
redblood cell
cheekcells
sperm
nervecell
musclecell
Amoeba
Paramecium

29. Similarities between plant cells
and animal cells
Both have a cell membrane surrounding
the cytoplasm
Both have a nucleus
Both contain mitochondria

30. Differences between plant cells
and animal cells
Animal cells Plant cells
Relatively smaller in
size
Irregular shape
No cell wall
Relativelylarger in
size
Regular shape
Cell wall present

31. Animal cells Plant cells
Vacuole small or absent
Glycogen granules as
food store
Nucleus at the centre
Large central vacuole
Starchgranules as
food store
Nucleus near cell wall
Differences between plant cells
and animal cells

33. ~ END ~