Biology form 4 chap2 pt1

1. CHAPTER 2 :
CELL STRUCTURE &
CELL ORGANISATION
2.1 Cell Structure & Function
2.2 Cell Organisation

2. 2.1 CELL STRUCTURE
& FUNCTION
Learning Outcomes :
2. Draw & label an animal cell and a plant cell
3. Identify the cellular components of an animal
cell & a plant cell
4. State the functions of the cellular components
in an animal and a plant cell
5. Compare & contrast an animal cell with a plant
cell
6. Relate the density of certain organelles with
the functions of specific cells.

4. HISTORY
 Robert Hooke (1665) was first
discovered the cell structure of
plant
 He examined fine slices of cork
with a primitive microscope
 He saw many ‘box-like’ structures ,
then he called ‘cells’, from Latin for
‘little rooms’.

5. THE CELL THEORY
(Schleiden M & Schwann T)
 All living organisms are made up of one or
more cells
 New cells are formed by the division of
pre-existing cells
 Cells contain genetic material of an
organism which is passed from the parent
cells to daughter cells
 Cells are the basic unit of structure &
function in living things

8.  ORGANELLES  specialised
structures which are each
surrounded by its own membrane &
perform specific function

9. PLASMA
MEMBRANE
 Thin, semi-permeable
 Made of protein, lipid
 Controls the
movement of
substances in and out
of the cell
 Non-organelle

10. CYTOPLASM
 Jelly-like substance
that contains water &
mineral salts
 Contains organelles
and food such as
carbohydrates
(glucose)
 Medium for metabolic
reactions
 Supplies the
substances required
by organelles
 Non-organelle

11. CELL WALL
 Thick layer outside
the plasma
membrane
 Made up of cellulose,
fully permeable
 Maintains the shape
of the plant cells
 Provides mechanical
support
 Non-organelle

12. NUCLEUS
 Spherical shape with
double membrane
 Contains nucleolus,
chromosomes,
nucleoplasm & nuclear
membrane
 Controls & regulates
all the activities of cell
 Contain the heredity
factors responsible for
the traits

13. RIBOSOME
 Small particles
consisting of RNA
 Exists freely in the
cytoplasm or on the
surface of the
endoplasmic
reticulum
 Synthesis of protein

14. ENDOPLASMIC RETICULUM
 A system of membrane-
enclosed tubules closely
packed together and
continuous with the nuclear
membrane
 RER has ribosome, SER
does not have
 Transport system for
protein & lipids within the
cell
 RER transport protein to
other part of cell
 SER stimulates the
synthesis of lipids &
cholesterol & transport
within the cell

16. GOLGI APPARATUS
 Vacuolar region surrounded
by a complex meshwork of
vesicles budding off at its end
 Received protein & lipids from
ER & modify them to form
specific secretion such as
enzymes & hormones
 Pack the secretions formed
into secreting vesicles &
transport them to plasma
membrane to be secreted
 Controls the secretory activity
of cells
 Formation of lysosomes

18. VACUOLE
 Filled with cell sap,
surrounded by semi-
permeable
membrane called the
tonoplast
 Contain water, sugar
& dissolved minerals
 Maintain turgidity of
cells in plants

19. MITOCHONDR
IA
 Rod-shape with a
double membrane
 Outer membrane is
smooth, inner
membrane is folded to
form cristae
 Known as ‘power-
house’ of the cell
 Releases energy as it
is the site for aerobic
respiration

21. CHLOROPLAST
 Disc-shape organelle
with a double
membrane
 Consist of an orderly
arrangement of grana
within the stroma.
Granum contains
chlorophyll
 Site of photosynthesis
 Trapped light energy
and change it into
chemical energy

22. LYSOSOMES
 Membrane-bound
vesicles found in animal
cells
 Contain enzymes which
control breakdown of
protein & lipids
 Contain enzymes that
digest aged or defective
cell components or
materials taken in by the
cell from its
environments such as
food particles or
bacteria.

23. CENTRIOLES
 A pair of
small
cylindrical
structures
(microtubules
)
 Form spindle
fibre for cell

24. COMPARE & CONTRAST
ANIMAL CELL SIMILARITIES PLANT CELL
A plasma membrane surrounding the
cytoplasm
Both contain nucleus & cytoplasm
Both contain organelles such as mitochondria,
ER, Golgi apparatus & ribosomes

25. ANIMAL CELL DIFFERENCES PLANT CELL
Smaller than plant cell SIZE Larger than animal cell
Irregular shape SHAPE Often regular in shape
Absent CELL WALL Present
Absent CHLOROPLAST Present
No large vacuoles. If VACUOLES Large central vacuole
present, small & filled with cell sap
numerous.
In a form of glycogen in FOOD STORAGE In a form of starch
liver & muscle tissues
Present CENTRIOLES Absent
Some animal cell have CILIA & FLAGELLA Absent
cilia or flagella

26. RELATIONSHIP BETWEEN THE
STRUCTURE OF AN ANIMAL CELL & A
PLANT CELL

27.  The number of specific organelles in a cell
varies on the type of cell and its function.
 Active cell  many mitochondria to provide
enough energy for its activities. Eg. : sperm
cells, flight muscle cell (insects & birds)
 Cell in meristems of plant shoot & root
 Green plants  more chloroplasts to carry out
photosynthesis such as palisade mesophyll cells
and spongy mesophyll cells, also guard cells.

28. EXERCISE 2.1
1. What are the organelle structures of a
cell?
2. What are the functions of each structure
describe above?