The function of cells

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

2. 2.1
CELL STRUCTURE
& FUNCTION
Learning Outcomes :
1.
2.
3.
4.
5.
Draw & label an animal cell and a plant cell
Identify the cellular components of an animal
cell & a plant cell
State the functions of the cellular components
in an animal and a plant cell
Compare & contrast an animal cell with a plant
cell
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 membraneenclosed 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 semipermeable
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 ‘powerhouse’ 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
A
PLANT CELL
plasma membrane surrounding the
cytoplasm
Both
Both
SIMILARITIES
contain nucleus & cytoplasm
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
present, small &
numerous.
VACUOLES
Large central vacuole
filled with cell sap
In a form of glycogen in
liver & muscle tissues
FOOD STORAGE
In a form of starch
Present
CENTRIOLES
Absent
Some animal cell have
cilia or flagella
CILIA & FLAGELLA
Absent

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