Golgi apparatus, its discovery its parts, location in cell and importance of Golgi in different mechanisms

1. TOPIC:
GOLGI APPARATUS.
PPRESENTED TO :
DR. SADIA IJAZ.
PRESENTED BY:
Members: GROUP 4.
1. IQRA MALIK.
2. AFRA IJAZ.
3. MINAHIL KHALID.
4. MANAHIL
KHANAM.
5. ARIBA NAMEEN.
6. ANEEQA SADIQ.

2. CONTENTS.
• INTRODUCTION.
• DEFINATION.
• OCCURANCE OF GOLGI APPARATUS.
• DISCOVERY OF GOLGI APPARATUS.
• HOW C.GOLGI OBSERVE GOLGI-
COMPLEX.
• STRUCTURE OF GOLGI APPARATUS.
• THE VESICULAR TRANSPORT MODEL.
• THE CISTERNAL MATURATION MODEL.
• SIZE AND NUMBER.
• LIPID COMPOSITION OF GOLGI-
APPARATUS.
• FUNCTION OF GOLGI APPARATUS.
• GLYCOSYLATION IN THE GOLGI
COMPLEX.
• REFERENCES.

3. INTRODUCTION.
• Golgi apparatus is also known as Golgi
Complex or Golgi bodies.
• It is universally found in both plants and
animal cells.
• It comprise of a series of five to eight cup-
shaped, membrane-covered
• Sacs called CISTERNAE .
• CISTERNAE that looks like a stack of
deflated balloons.

4. DEFINATION.
“A CYTOPLASMIC ORGANELLE
THAT CONSISTS OF A STACK OF
SEVERAL MEMBRANOUS
SACCULES AND ASSOCIATED
VESICLES ACTIVE IN THE
MODIFICATION AND
TRANSPORT OF PROTEINS”

5. OCCURRANCE.
 Golgi Apparatus is
located in the
cytoplasm , after
the Endoplasmic
Reticulum , near
the nucleus of the
cell.

6. DISCOVERY OF GOLGI
APPARATUS.
• For ages the GOLGI APPARATUS was supposed as an
artifact(i.e. an artificial structure formed during preparation for
microscopy)of several fixation and staining procedures.
• In other words, many scientists thought that the structure
observed during several microscopy procedures and termed
the GOLGI did not actually exist in the living cells.
• Not until ELECTRON MICROSCOPE studies were performed
in the 1960s was the GOLGI recognized and accepted as a
legitimate cell organelle.

7. CONNTINUE…
 THE GOLGI APPARATUS WAS FIRST DESCRIIBED IN 1898
BY
CAMILLO GOLGI ,A PIONEER OF CYTOLOGY AND
CYTOCHEMISTRY.
• THOUGH GOLGI STATED THE STRUCTURE AS THE
“INTERNAL RETICULAR AAPPARRATUS”OF THE
CELL,THE ORGGANELLE WAS LATER RENAMED IN HIS
HONOUR .
• C.GOLGI RECEIVED THE NOBLE PRIZE IN 1906 FOR HIS
SEVERAL CYTOLOGICAL DISCOVERIES AND HIS
CYTOCHEMICAL AND HISTOCHEMICAL INNOVATIONS.

8. HOW C.GOLGI OBSEERVES
GOLGI COMPLEX.
• IN Golgi, s early studies of nervous
tissue , he established a staining
technique that he referred to as
reazione nera ,meaning “BLACK
REACTION”, it is known as the
GOLGI stain.
• In this technique , nervous tissue is
fixed with potassium dichromate
and then suffused with silver nitrate.
• While examining neurons that he
stained by using his black reaction
,GOLGI identified an “internal
reticular apparatus”.
• This structure became known as the
GOLGI APPARATUS

9. CONTINUE…
• After its original explanation , GOLGI APPARATUS
persisted as a debatable cell structure because it was
not readily identifiable in all cells.
• To visualize these organelles , GOLGI employed stains
containing silver ,osmium and other heavy metals, and
it was believed by many other cytologists that organelle
was an artifact produced by precipitation of the metal
within the cell.
• In 1950,s the existence of the apparatus was confirmed
by ELECTRON-MICROSCOPE studies ;these studies
also shed light on the detail of the the apparatus
organization.

10. STRUCTURE OF GOLGI
APPARATUS..
• The GOLGI is a complex organelle , composed
of a single compartment that is folded into sacs
that appeared to be stacked on top of one
another.
• Each sac (called a cistern ; plural cisternae )is
considered an isolated sub compartment of the
GOLGI,
• The chemical reaction occur in each sac are
different, achieved by a unique compliment of
enzyme .
• The GOLGI CISTERNA are arranged in a
specific order so that proteins enter on the
either side of the GOLGI APPARATUS ,move
progressively through adjacent cisternae until
they emerged from the opposite side.

11. CONTINUE…
• The side facing the nucleus is called CIS FACE ,and the opposite face is
called as TRANS FACE.
• Current model of the structure of the GOLGI APPARARUS ,is based on
some 25 years of transmission ,and SCANNIG ELECTRON MICROSCOPIC
study as well as biochemical studies of isolated GOLGI MEMBRANES .
• Through GOLGI BODIES vary slightly in organization from one type of
tissue to another, they usually take the form of a stack of flattened ,oval
cisternae surrounded at their circumferential edges above and below by
vesicles and tubular structure.
• GOLGI BODIES are also known as DICTYOSOME, which means “STACK
LIKE BODIES” .
• In most animal cells. The number of the number of GOLGI CISTERNAE is
5 or 6 , the LUMEN of each cisternae varying in width from about 500 to
1000nm .

12. CONTINUE…
• The Golgi bodies of plant cells
often have 20 or more cisternae.
The margins of each cisternae are
slightly curved so that
• The entire Golgi body takes on a
bow like appearance. The
cisterna at the convex end of the
dictyosome comprises what is
called the cis face or forming face,
• and the cisterna at the concave end
comprises the trans face or
maturing face.

13. • The vesicles near the trans face are larger and
are believed to be formed from the uppermost
cisterna.
• Small vesicles may also be discharged from the
margins of the cisternae that are between cis and
trans faces.
• Recent scanning electron photomicrographs of
Golgi bodies reveal a structure that is remarkably
consistent with models of the organelle based
solely on transmission studies.
The small vesicles that are adjacent to the cis face
that are supposed to fuse with and contribute
additional structure to the Golgi body.

14. • In many cells specially in which the Golgi bodies’ main function is
related to secretion the faces of Golgi bodies are arranged in a
specific manner.
• The forming face is located next to either the nucleus or a
specialized portion of the ER that lacks bound ribosomes and is
called “transitional” ER.
• The maturing faces is usually directed toward the plasma
membrane it is believed that the nuclear membrane and ER are the
source of small vesicles that fuse with the cis face whereas some of
the larger vesicles arising from the maturing face are secretary
vesicles and subsequently fuse with the plasma membrane

15. • .

16. ER AND GOLGI
 Synthesis in ER but modification in Golgi
 Similar to an assembly line
 Options packages are added in Golgi
 Sequential passage through cisternae (cis
to trans)
 Each cisternae contains different enzymes

17. VESICLE ORGANELLES
 Perform many of the renewal functions
 Lysosome
 Peroxisome
 Glyoxisome

18. LYSOSOME
 Contains digestive enzymes used to degrade macromolecules or
organelles
 Originates in ER but enzymes are activated in Golgi
 Important in macrophages for degradation of particles acquired via
phagocytosis
 Used to degrade organelles-autophagy

19. Nucleus 1 µm
Lysosome
Lysosome
Digestive
enzymes
Plasma
membrane
Food vacuole
Digestion
(
(b) Autophagy

20. Nucleus 1 µm
Lysosome
Lysosome
Digestive
enzymes
Plasma
membrane
Food vacuole
Digestion
a) Phagocytosis

21. (1) THE VESICULAR
TRANSPORT MODEL:-
•One of the principal observations by Rothman’s
group was that the vesicles that formed in golgi
moved cargo proteins between cisternae from the
Cis face to Trans face.
•These observations supported the vesicular
transport model originally developed and advocated
by George Palade and Marilyn Farquhar in 1998.
•The vesicular transport model suggests that the
golgi cisternae are stable compartments that house
certain protein modification enzymes that function
to add or remove sugars , add sulfate groups , and
perform other modifications.

22. • Vesicles arrive at each cisterna carrying
cargo proteins , which are then modified by
the resident enzymes located within that
cisterna.
• Next , new vesicles carrying the cargo
proteins bud from the cisterna and travel to
the next stable cisterna , where the next
series of enzymes further processes the
protein cargo.

23. (2) THE MATURATION
MODEL:-
•Before the work of Palade , Farquhar ,
Rothman and others who analyzed the
vesicles moving proteins between Golgi
cisternae , scientists thought that each Golgi
cisternae was transient and that the cisternae
themselves moved from the Cis to the Trans
fsce of the Golgi , changing over time.

24. • The movement of proteins as passengers
within cisternae through the Golgi stack is
called the “Cisternal maturation model”.

25. • This model proposes that the enzymes
present in each individual Cisterna change
over time , while the cargo proteins remain
inside the Cisterna .
• Before Rothman’s work on vesicles , this
model had broad support.
• However , once scientists identified the large
numbers of small transport vesicles
surrounding the Golgi , researches developed
the vesicular transport model as an updated
replacement.

27. SIZE & NUMBER
The size and number of Golgi bodies varies from one
type of cell to another and according to the cell’s
metabolic activity.
The organelle is thought of as being almost
continuously in a state of flux.
Some cells are reported to have only one Golgi body
and others may have hundreds.
Because one of the major functions of Golgi apparatus
is secretions, it is not surprising that a size and
number of Golgi bodies increase during periods of
active cellular secretion.

28. •In plant cells, the number of Golgi bodies
increases during cell division when these
organelles secrete materials that forms the cell
plates, which then develops into the cell wall that
separates two new cells.
The goblet cells found in the intestinal epithelium
contain only a single, large Golgi body located in
the region of the cell where mucigen granules are
stored prior to their secretions. In these cells, the
size of Golgi bodies increases dramatically during
periods of digestive activity.

29. •On average, the membrane-enclosed organelles together occupy
nearly half the volume of a eukaryotic cell, and the total amount of
membrane associated with them is enormous.
The relative volumes and numbers of major membrane organelles in Hepatocytes
(liver cells).

30. LIPID COMPOSITION OF
GOLGI APPARATUS:-
•A cell comprises many kinds of membranes, each
with unique properties given by its particular mix of
lipids and proteins.
. Several phenomena contribute to these differences. For example,
differences between membranes in the endoplasmic reticulum
(ER) and the Golgi are largely explained by the fact that
phospholipids are synthesized in the ER , whereas sphingolipids
are synthesized in the Golgi.
. As a result, the proportion of sphingomyelin as a
percentage of total membrane lipid phosphorus is about
six times as high in Golgi membranes as it is in ER
membranes.

32. Functions Of Golgi Apparatus
Secretion
Synthesis
Sulfation
Apoptosis
Phosphorylation
Cell-Specific Functions

33. 1.Secretion
 Although the golgi apparatus is involved in
many different cellular processes ,its principle role in many cell is
in secretion.
 Golgi plays an important role in the synthesis of proteoglycans
,which
are molecules present in the extracellular matrix of animals.

34. Secretion
The Golgi apparatus is
involved in cell secretions;
secretory vesicles are also
shown ,which break off the
membranes
and transport materials to the
cell membrane.

35. Diagram of secretory process from
endoplasmic reticulum to Golgi apparatus.
1. Nuclear Membrane.
2. Nuclear Pore.
3. Rough Endoplasmic Reticulum.
4. Smooth Endoplasmic Reticulum.
5. Ribosomes attached to RER.
6. Macromolecules.
7. Transport Vesicles.
8. Golgi Apparatus.
9. Cis face of Golgi Apparatus.
10.Trans face of Golgi Apparatus.
11.Cisternae of the Golgi Apparatus.
Path Of Secretion

36. 2.Synthesis
 It is also a major site of carbohydrate
synthesis.
 This includes the production of glycosaminoglycans ,long
unbranched polysaccharides which the golgi then attaches to a protein
synthesized
in the endoplasmic reticulum to form proteoglycans.
 Enzymes in the Golgi polymerize several of these GAGs via
xylose link on the core protein.

37. 3.Sulfatio
n Another task of the Golgi involves the Sulfation (Adding of sulpho group)
certain molecules
passing through its lumen via sulfotransferases that gain their sulfer
molecule
from a donor called PAPS.
 This process occur in GAGs of proteoglycans as well as on the core protein.
 Sulfation is generally performed in the trans-Golgi network.
 The level of sulfation is very important to the proteoglycans’
signaling abilities as well as giving the proteoglycan its overall
negative charge.

38. CELL RENEWAL
 Cells and their molecules age and become less
effective
 An important cellular function is renewal
 Old molecules and organelles are recycled
 New phospholipids are produced for the membrane
 Toxic molecules need to be collected and detoxified
 Sometimes a cell needs to commit suicide
 Called autolysis or apoptosis

39. CELL DEATH
 Sometimes used in development of organism
 Hand development
 Certain cells are programmed to die at appropriate
times
 Defense against viral or intracellular bacterial
infections
 Self-destruct
 Program is started by T cells
 Apoptosis is often accomplished by leaky or popping
lysosomes

40. 4. Apoptosis
 The Golgi has a putative
role in apoptosis.
 A newly characterized
protein , GAAP (Golgi
anti-apoptotic protein),
almost exclusively
residues In the golgi and
protects cells from
apoptosis by an as-yet
undefined mechanism.

41. 5. Phosphorylation
 The phosphorylation of molecules requires energy in the form of ATP.
 The ATP is imported into the lumen of the Golgi which is utilized by kinases
such as casein kinase 1 and casein kinase 2.
 One molecule that is phosphorylated in the Golgi is Apolipoprotein ,which
forms a molecule known as VLDL that is a constituent of serum blood
 It is thought that the phosphorylation of these molecules is important to
help aid in their sorting for secretion into the blood serum.

42. VESICULAR TRANSPORT
 Vesicles leaving RER transported to the Cis face of Golgi Apparatus ,fuse
with the membrane and empty the contents into the lumen.
 Molecules inside the lumen are modified and sorted for transport to the next
destination.
 Proteins destined for places other than ER and GA, moves to TRANS face.
OR
 The Golgi Apparatus are moved through the golgi Cisternae towards the
trans face ,to a complex network of membranes and associated vesicles
known as trans-Golgi network(TGN).

43. STEP 1
Proteins and lipids
that are made on
the ER membranes
are transported
through the ER and
are packaged in
transport vesicles
that bud off from the
ER.

44. STEP 2
The vesicles fuse
with the membrane
of the Golgi bodies,
dumping their
contents into the
Golgi.

45. STEP 2
The vesicles fuse
with the
membrane of the
Golgi bodies,
dumping their
contents into the
Golgi.
STEP 3
Once inside the
Golgi bodies, the
molecules take
one of many
paths. Many
become tagged
with
carbohydrates.

46. STEP 3
Once inside the
Golgi bodies, the
molecules take
one of many
paths. Many
become tagged
with
carbohydrates.

47. STEP 4
The molecules
collect at the ends
of the fold in the
Golgi bodies.
Vesicles pinch off
and carry the
molecules to other
parts of the cell or
to the plasma
membrane where
they will be
secreted to the
outside of the cell

48. PROTEIN
MODIFICATION
Proteins going to organelles or outside
of the cell must be modified so that they
are delivered
Modifications happen when specific
sugar molecules are added to a core
oligosaccharide that is attached to a
protein
These sugar molecules are required for
proper delivery

49. •One example is Mannose 6-phosphate which is important in glycolysis
•Enzymes synthesized in the ER are delivered to the Golgi body via a
transport vesicle, and in the cis-face specific sugars are added to the
protein
•Eventually, once the enzyme has arrived at the trans-face, it has the
required Mannose 6-phosphate
•Receptors receive the enzyme, it is transported via a vesicle, and when
it arrives at the endosome, the enzyme is released and the phosphate
removed

50. Some types of coated vesicles also originate from
Golgi apparatus such as following

51. Cell Tissue or Organ Golgi Function
Exocrine Pancreas Secretion of Zymogen
(protease, lipases, carbohydrase, and nucleases)
Gland cell Parotid gland Secretion of Zymogen
Goblet cell Intestinal epithelium Secretion of mucus and zymogen
Follicle cell Thyroid gland Pretyhroglobulin
Plasma cell Blood Immunoglobulins
Myelocytes, sympathetic
ganglia
Schwann cells
Nervous tissue Sulfation reactions
Endothelial cells Blood vessels Sulfation reactions
Liver cells Liver Lipid secretions
Alveolar epithelium Mammary gland Secretion of milk proteins
Paneth cells Intestines Secretion of proteins
Brunner’s gland cell Intestines Synthesis and secretion of mucopolysaccharides,
enzymes, hormones
Connective tissue Amblystoma limb Synthesis and secretion of collagen
Cornea Avian eye Secretion of collagen
Plant cells Most Secretion of pectin and cellulose
Cell Specific Functions of
Golgi Apparatus

52.  The Golgi Complex sometimes creates autoantibodies that
are found in Autoimmune diseases.
were first identified in the
serum of a Sjögren’s syndrome patient with lymphoma.
Anti-Golgi complex antibodies are also found in:
 Systemic lupus erythematosus
 Rheumatoid Arthritis
HIV carriers
Anti-Golgi complex antibodies are considered rare when
compared to other classic autoantibodies such as anti-
chromatin.

53. ALZHEIMER’S DISEASE
AND GOLGI
 Golgi apparatus is found to play an
important role in Alzheimer’s
disease.
 Alzheimer’s disease is a brain
disorder where brain cells are being
destroyed. This is what gives a
person memory loss and this
disease can lead to death.
 As the death of neurons increases
the affected brain region begins to
shrink. The cause of this disease is
because there is too little removal of
a specific type of protein.
 Therefore, the Golgi apparatus isn’t
functioning as it is suppose to in
collecting, transporting, and
distributing the protein molecules.

54. 1. Cells by Michael W. Berns
2. Cell and Molecular Biology by Phillip. Sheeler and
Donald E. Bianchi
3. Principles of Cell Biology by George Plopper 2nd Edition
4. Molecular Cell Biology by Lodish 2008
5. Cell and Molecular Biology by G. Karp
6th Edition