organelles of cytoplasm structure and function

1. SURYAGOPAN.P
1st yr MDS
ORAL PATHOLOGY

2. CONTENT
• INTRODUCTION
• ORGANELLES IN
CYTOPLASM
• ENDOPLASMIC
RETICULUM
• GOLGI APPARATUS
• LYSOSOMES
• PEROXISOMES
• CENTROSOMES AND
CENTRIOLES
• SECRETORY VESICLES
• MITOCHONDRIA
• NUCLEUS
• RIBOSOME
• CYTOSKELITON
• CONCLUSION

3. INTRODUCTION
• Cytoplasm is a gel like fluid present between
plasma membrane and nucleus.
• It contains a clear liquid portion called cytosol
which contains various substances like
proteins, carbohydrates, lipids and
electrolytes.
• Apart from these substances many organelles
are also present in cytoplasm.

4. CYTOPLASM

5. FUNCTION OF CYTOPLASM
• BREAKING DOWN WASTE
• HELP METABOLIC ACTIVITY
• GIVE THE CELL IT’S SHAPE
• KEEP ORGANELLES IN PLACE

6. ORGANELLES IN CYTOPLASM
• All the cells in the body contain some
common structures called organelles in the
cytoplasm.
• Some organelles are bound by limiting
membrane and others do not have limiting
membrane.

7. THE ORGANELLES WITH LIMITING
MEMBRANE
• ENDOPLASMIC RETICULUM
• GOLGI APPARATUS
• LYSOSOME
• PEROXISOME
• CENTROSOMES AND CENTRIOLES
• SECRETORY VESICLES
• MITOCHONDRIA
• NUCLEUS

8. THE ORGANELLES WITHOUT LIMITING
MEMBRANE
• RIBOSOMES
• CYTOSKELITON

9. ENDOPLASMIC RETICULUM
• Endoplasmic reticulum is made up of tubules
and microsomal vesicles.
• These structures form an interconnected
network which acts as the link between the
organelles and cell membrane.

10. TYPES OF ENDOPLASMIC RETICULUM
• ROUGH ENDOPLASMIC RETICULUM
• SMOOTH ENDOPLASMIC RETICULUM

11. ROUGH ENDOPLASMIC RETICULUM
• Rough endoplasmic reticulum is the one to
which granular ribosome is attached.
• This gives the rough appearance, so it is called
rough endoplasmic reticulum.
• It is also called granular endoplasmic
reticulum.

12. FUNCTIONS OF ROUGH ENDOPLASMIC
RETICULUM
• SYNTHESIS OF PROTEINS
• DEGRADATION OF WORN OUT ORGANELLS

13. SMOOTH ENDOPLASMIC RETICULUM
• It is also called as agranular endoplasmic
reticulum because of its smooth appearance
without the attachment of ribosome.
• It is formed by many interconnected tubule,
so it is also called tubular endoplasmic
reticulum.

14. FUNCTIONS OF SMOOTH
ENDOPLASMIC RETICULUM
• SYNTHESIS OF LIPIDS AND STEROIDS
• ROLE IN CELLULAR METABOLISM
• STORAGE AND METABOLISM OF CALCIUM
• CATABOLISM AND DETOXIFICATION OF TOXIC
SUBSTANCES

15. GOLGI APPARATUS
• It is also called Golgi body or Golgi complex.
• It is present in all the cells except red blood
cells.
• It consists of 5-8 flattened membranous sac
called cisternae.
• It is situated near the nucleus.
• It has two ends or faces namely cis face and
trans face.

16. ..

17. FUNCTIONS OF GOLGI APPARATUS
• It is concerned with the processing and
delivery of substances like protein and lipids
to different parts of cell.
• It functions like post office because it packs
the processed materials into secretory
granules, secretory vesicles and lysosomes
and dispatch them either out of the cell or to
another part of the cell.

18. LYSOSOMES
• Lysosomes are small globular structures filled
with enzymes.
• These enzymes are synthesised in rough
endoplasmic reticulum and transported to the
Golgi apparatus.
• Here these are processed and packed in the
form of small vesicles.
• Then these vesicles are pinched off from Golgi
apparatus and become lysosomes.

19. TYPES OF LYSOSOMES
• PRIMARY LYSOSOMES- It is pinched of from
Golgi apparatus. It is inactive in spite of having
the hydrolytic enzyme.
• SECONDARY LYSOSOME- It is active lysosome
formed by fusion of primary lysosome with
phagosome or endosome.

20. FUNCTIONS OF LYSOSOMES
• Digestion of unwanted substances
• Removal of excess secretory products in the
cells.
• Secretory function

21. PEROXISOMES
• Peroxisomes are otherwise called as
microbodies.
• These are pinched off from endoplasmic
reticulum.
• Peroxisomes contains some oxidative enzymes
such as catalase, urate oxidase and D- amino
acid oxidase.

22. FUNCTIONS OF PEROXISOMES
• Degrade the toxic substance like hydrogen
peroxide and other metabolic products by means
of detoxification.
• Form the major site of oxygen utilization in the
cells.
• Breakdown the excess fatty acid.
• Accelerate gluconeogenesis from fat.
• Degrade purine to uric acid
• Participate in the formation of myelin and bile
acids.

23. CENTROSOMES AND CENTRIOLES
• The centrosome is situated near the centre of
the cell close to the nucleus.
• It consist of two cylindrical structures called
centrioles which are responsible for the
movement of chromosomes during cell
division

24. SECRETORY VESICLES
• The secretory vesicles are globular structures,
formed in the endoplasmic reticulum and
processed and packed in the Golgi apparatus.
• When necessary the secretory vesicles rupture
and release the secretory substance into the
cytoplasm.

25. MITOCHONDRION
• Mitochondrion is a rod or oval shaped
structure with a diameter of 0.5 to
1micrometer.
• It is covered by a double layered membrane.
• The outer membrane is smooth and encloses
the content of mitochondrion.
• The inner membrane forms many folds called
cristae and covers the inner matrix space.

26. MITOCHONDRION FUNCTIONS
• Production of energy
• Synthesis of ATP
• Initiation of apoptosis

27. NUCLEUS
• Nucleus is present in those cells which divide
and produce enzyme.
• The cell with nucleus are called eukaryotes
and those without nucleus are called as
prokaryotes(eg.RBC)
• Most of the cells have only one
nucleus(uninucleated).Few types of cells like
skeletal muscle cells have many
nuclei(multinucleated)

28. STRUCTURE OF NUCLEUS
• NUCLEAR MEMBRANE
• The nucleus is covered by a
double layered membrane
called nuclear membrane.
• It encloses a fluid called
nucleoplasm.
• Nuclear membrane is
porous and permeable in
nature and it allows
nucleoplasm to
communicate with
cytoplasm.

29. STRUCTURE OF NUCLEUS
NUCLEOPLASM
• It is a gel like ground
substance and contains
large quantities of genetic
material in the form of DNA.
• The DNA is made up of
chromatin threads.
• These chromatin threads
become the rod shaped
chromosomes just before
the cell division.
NUCLEOLI
• One or more nucleoli are
present in each nucleus.
• The nucleolus contain RNA
and some proteins which
are similar to those found in
ribosomes.
• The RNA is synthesised by
chromosomes and stored in
nucleolus.

30. FUNCTION OF NUCLEUS
• Controls all the activity of the cell
• Synthesizes RNA
• Form subunit of ribosomes
• Sends genetic instructions to the cytoplasm for
protein synthesis through mRNA
• Controls the cell division through genes
• Stores the hereditary information and transforms
this information from one generation of the
species to next

31. RIBOSOMES
• Ribosomes are small granular structures with
a diameter of 15nm.
• Some ribosomes are attached to rough
endoplasmic reticulum while others are
present as free ribosomes in the cytoplasm
• The ribosome are made up of proteins(35%)
and RNA(65%).
• The RNA present in ribosome are called as
ribosomal RNA(rRNA)

32. FUNCTIONS OF RIBOSOME
• SYNTHESIS OF PROTEINS

33. CYTOSKELETON
• The cytoskeleton of the cell is a complex network that
gives shape, support and stability of the cells.
• It is also essential for the cellular movements and the
response of cell to external stimuli.
• The cytoskeleton consist of 3 major protein
components.
A. Microtubules
B. Intermediate filaments
C. Microfilaments

34. MICROTUBULES
• Microtubules are straight and hollow tubular
structures formed by bundles globular protein
called alpha and beta tubulin.
• FUNCTION- Determine the shape of cell
• Give structural strength to the cell
• Act like conveyer belt which allow the
movement of granules, vesicles protein
molecules and some organelles like
mitochondria to different part of cell.

35. INTERMEDIATE FILAMENTS
• The intermediate filaments form a network
around the nucleus and extend to the
periphery of the cell.
• These filaments are formed by fibrous
proteins and help to maintain the shape of the
cell.
• The adjacent cells are connected by
intermediate filaments by desmosomes.

36. MICROFILAMENTS
• Microfilaments are long and fine thread like
structures which are made up of non tubular
contractile proteins called actin and myosin.
• FUNCTIONS-
• Give structural strength to the cell
• Provide resistance to the cell against the
pulling forces
• Responsible for cellular movements like
contraction, gliding and cytokinesis.

37. CONCLUSION
• CYTOPLASM IS NEEDED FOR MANY
FUNCTIONS AND WITHOUT IT NO CELL CAN
FUNCTION.