working of Cell Organelles.

1. Presentation
of
Working of Cell Organelles

2. INTRODUCTION
 Types of cell
 Organelles of cell
 Working of organelles

3. Types of Cell
1.Eukaryotic cell
2.Prokaryotic cell
Types of Cell

4. Eukaryotic cell
Eukaryotic cells are found in the
kingdoms Protista, Plantae,
Fungi, and Animalia.
They have a nucleus and
membrane enclosed organelles.

5. Eukaryotic cells contain well
defined cellular organelles
such as:
 Nucleus
 Mitochondria
 Endoplasmic reticulum
 Golgi apparatus
 Peroxisomes
 Lysosomes
 Plastids
 Vacuoles
 centrosome

6. The nucleus is the largest cellular organelle in
animals. In mammalian cells, the average
diameter of the nucleus is approximately 6
micrometers (μm), which occupies about 10%
of the total cell volume. The viscous liquid
within it is called nucleoplasm, and is similar
in composition to the cytosol found outside
the nucleus. It appears as a dense, roughly
spherical organelle.
Nucleu
s

7. function of nucleus
The cell 'Nucleus' controls all cell activity by
regulating what proteins are made. The cell
contains DNA and transmits messages by
eating, movement, and reproduction. This is
a large organelle that is easily seen with a
light microscope

9. In electron micrographs of cells, mitochondria
appears as – rods, spheres or filamentous bodies.
Size: 0.5µm -1µm
in diameter
up to 7µm
in length
MITOCHONDRIA

10. Working of mitochondria
Mitochondria convert oxygen, and the sugar,
fat and protein from foods to useable
energy. The body uses that energy for daily
function and growth.

11. make energy from
sugar + O2 = ATP

12. Cytoplasm of eukaryotic cells
contain a network of
interconnecting membranes.
This extensive structure is called
endoplasmic reticulum.
This is of two type:-
1.Smoth ER
2.Rough ER
ENDOPLASMIC RETICULUM

13. Rough Endoplasmic Reticulum
 These membranes enclose a lumen.
 In this lumen newly synthesized proteins are modified.
 Rough appearance is due to the presence of ribosomes
attached on its cytosolic side(outer side).
 These ribosomes are involved in the biosynthesis of
proteins.

14. Smooth Endoplasmic Reticulum
Smooth Endoplasmic Reticulum
 Smooth endoplasmic reticulum is involved in lipid
synthesis.
 Cholesterol synthesis
 Steroid hormones synthesis.
 Detoxification of endogenous and exogenous
substances.
 The enzyme system involved in detoxification is called
Microsomal Cytochrome P450 monooxygenase
system(xenobiotic metabolism).

15. Golgi complex is a network of
flattened smooth membranous
sacs- cisternae and vesicles.
These are responsible for the
secretion of proteins from the
cells(hormones, plasma
proteins, and digestive
enzymes).
It works in combination with
ER.

16. Working of Golgi apparatus
Golgi apparatus packages macromolecules
for secretion and transportation outside the
cell. It produces vesicles that encloses the
macrolecules and transports it to the plasma
membrane.
It works with the rough and smooth
endoplasmic reticulum

17. These are responsible for
the intracellular digestion
of both intra and
extracellular substances.
They have a single limiting
membrane.
They have an acidic pH- 5
They have a group of
enzymes called
Hydrolases.

19. Working of Lysosomes
Lysosomes contain acid hydrolase enzymes
to break up waste materials and cellular
debris. Lysosomes fuse with vacuoles and
dispense their enzymes into the vacuoles,
digesting their contents.

20.  Called Peroxisomes because of their
ability to produce or utilize H2O2.
 They are small, oval or spherical in shape.
 They have a fine network of tubules in
their matrix.
 About 50 enzymes have been identified.
 The number of enzymes fluctuates
according to the function of the cells.
PEROXISOMES

21. Working of peroxisome
A major function of the peroxisome is the breakdown of
fatty acid molecules, in a process called beta-oxidation. In
this process, the fatty acids are broken down two carbons
at a time, converted to Acetyl-CoA, which is then
transported back to the cytosol for further use. In animal
cells, beta-oxidation can also occur in the mitochondria. In
yeast and plant cells, this process is exclusive for the
peroxisome.

22.  The plastid (Greek: πλαστός; plastós: formed, molded –
plural plastids) is a major organelle found in
the cells ofplants and algae. Plastids are the site of
manufacture and storage of important chemical
compounds used by the cell. They often
contain pigments used in photosynthesis, and the types
of pigments present can change or determine the cell's
color. They possess a double-stranded DNA molecule,
which is circular, like that of prokaryotes.
Plastid

23. 1. Leucoplast: These are colourless plastids. They store the food of the
plant body in the form of starch, proteins and fat. They are mostly
present in the storage cell as in the roots and underground stem.
2. Chloroplast: These are green coloured plastids because of the
presence of the chlorophyll. They occur abundantly in green leaves
and also in green parts of the shoot. They trap the solar energy which
is used for manufacturing food. So, they are the sites of
Photosynthesis.
3. Chromoplast: These are colored plastids. They provide colour to
fruit and plants. So they help in pollination and fuit dispersal.
Plastid types

24. Function of plastids:
• Chloroplast traps the solar energy and
transform in to the chemical energy of
carbohydrate using water and CO2 this
process is called photosynthesis.
• Chloroplast impart colors to the
different flowers which have to attract
insects for pollination.
• Leucoplasts store food in the form of
starch.

25. A vacuole is a
membrane-bound
organelle which is
present in all
plant and fungal
cells and some
protist, animal
and bacterial
cells.
vacuole

26. Function of vacuole
Isolating materials that might be harmful or a threat to the cell
Containing waste products
Maintaining internal hydrostatic pressure or turgor within the cell
Maintaining an acidic internal pH
Containing small molecules
Exporting unwanted substances from the cell

27. In cell biology, the
centrosome is an organelle
that serves as the main
microtubule organizing
center of the animal cell
as well as a regulator of
cell-cycle progression.
centrosome

28. Function of Centrosomes

It is the center of production of microtubules, the thin filamentous
structures in the cell.
 Centrosomes and the associated microtubules determine the directional
growth of certain types of cells such as neurons, where the direction and
point of growth of axons are determined by these cells.
 They are known as the chief microtubule organizing centers of the animal
cells.
They are responsible for the initiation of cytokinesis, or splitting up of the
mother cell into two.
 In the absence of centrosomes, it has been observed that cytokinesis
does not initiate even after the completion of mitosis.

They organize the primary cilia that are present on the epithelial cells of
the kidney, the olfactory receptors, the lining of the stomach, and rod
cells in the eyes.

29. Thank you………