Sweet and Short PPT on Golgi Apparatus

1. GolgiApparatus
Parthasarathy
IX-RosesGolgi Apparatus @ Parthasarathy.M

2. INTRODUCTION
 The Golgi apparatus (/ɡoʊldʒiː/), also known as the Golgi complex, Golgi body,
or simply the Golgi, is an organelle found in most eukaryotic cells.It was identified
in 1897 by the Italian physician Camillo Golgi and named after him in 1898.
 Part of the cellular endomembrane system, the Golgi apparatus packages
proteins into membrane-bound vesicles inside the cell before the vesicles are
sent to their destination.
Golgi Apparatus @ Parthasarathy.M

3.  The Golgi apparatus resides at the intersection of the secretory, lysosomal, and
endocytic pathways. It is of particular importance in processing proteins for secretion,
containing a set of glycosylation enzymes that attach various sugar monomers to
proteins as the proteins move through the apparatus.
DISCOVERY
 Owing to its large size and distinctive structure, the Golgi apparatus was one of the
first organelles to be discovered and observed in detail. It was discovered in 1898 by
Italian physician Camillo Golgi during an investigation of the nervous system.
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4. GOLGI APPARATUS
Diagram of a single "stack" of Golgi
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5.  After first observing it under his microscope, he termed the structure theinternal
reticular apparatus.
 Some doubted the discovery at first, arguing that the appearance of the structure
was merely an optical illusion created by the observation technique used by Golgi.
 With the development of modern microscopes in the 20th century, the discovery was
confirmed.
 Early references to the Golgi referred to it by various names including the "Golgi–
Holmgren apparatus", "Golgi–Holmgren ducts", and "Golgi–Kopsch apparatus".
 The term "Golgi apparatus" was used in 1910 and first appeared in scientific literature in
1913.
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6. CAMILLO GOLGI
Camillo Golgi 7 July 1843 –21 January
1926) was an Italian physician,
biologist, pathologist, scientist, and
Nobel laureate. Several structures and
phenomena in anatomy and
physiology arenamed for him,
including the Golgi apparatus, the
Golgi tendon organ and the Golgi
tendon reflex.
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7.  He is recognized as the greatest neuroscientist and biologist of his time.
Biography
 Camillo Golgi was born in July 1843 in the village of Corteno, in the province of
Brescia (Lombardy), Italy. The village is now named Corteno Golgi in his honour.
 His father was a physician and district medical officer. Golgi studied at the University
of Pavia, where he worked in the experimental pathology laboratory under Giulio
Bizzozero, who elucidated the properties of bone marrow. He graduated in 1865. He
spent much of his career studying the central nervous system.
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8. SUBCELLULAR LOCALIZATION
 Among eukaryotes, the subcellular localization of the Golgi apparatus differs. In
mammals, a single Golgi apparatus complex is usually located near the cell
nucleus, close to the centrosome. Tubular connections are responsible for linking
the stacks together.
 Localization and tubular connections of the Golgi apparatus are dependent
on microtubules. If microtubules are experimentally depolymerized, then the Golgi
apparatus loses connections and becomes individual stacks throughout
the cytoplasm.
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9. STRUCTURE
 In most eukaryotes, the Golgi apparatus is made up of a series of compartments
consisting of two main networks: the cis Golgi network (CGN) and the trans Golgi
network (TGN). The CGN is a collection of fused, flattened membrane-enclosed
disks known as cisternae (singular: cisterna), originating from vesicular clusters that
bud off the endoplasmic reticulum.
 A mammalian cell typically contains 40 to 100 stacks. Between four and eight
cisternae are usually present in a stack; however, in some protists as many as sixty
cisternae have been observed. This collection of cisternae is broken down into cis,
medial, and trans compartments.
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10. FUNCTION
 The Golgi apparatus is a major collection and dispatch station of protein products
received from the endoplasmic reticulum (ER). Proteins synthesized in the ER are
packaged into vesicles, which then fuse with the Golgi apparatus. These cargo
proteins are modified and destined for secretion via exocytosis or for use in the
cell.
 In this respect, the Golgi can be thought of as similar to a post office: it packages
and labels items which it then sends to different parts of the cell or to
the extracellular space. The Golgi apparatus is also involved in lipid transport
and lysosome formation.
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11.  The structure and function of the Golgi apparatus are intimately linked. Individual
stacks have different assortments of enzymes, allowing for progressive processing of
cargo proteins as they travel from the cis to the trans Golgi face. Enzymatic reactions
within the Golgi stacks occur exclusively near its membrane surfaces, where enzymes
are anchored.
 This feature is in contrast to the ER, which has soluble proteins and enzymes in
its lumen. Much of the enzymatic processing is post-translational modification of
proteins. For example, phosphorylation of oligosaccharides on lysosomal proteins
occurs in the early CGN.
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12. VESICULAR TRANSPORT
 The vesicles that leave the rough endoplasmic reticulum are transported to
the cis face of the Golgi apparatus, where they fuse with the Golgi membrane and
empty their contents into the lumen. Once inside the lumen, the molecules are
modified, then sorted for transport to their next destinations.
 Those proteins destined for areas of the cell other than either the endoplasmic
reticulum 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 the trans-Golgi network (TGN).
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13. BREFELDIN A
 Brefeldin A (BFA) is a fungal metabolite used experimentally to disrupt the
secretion pathway as a method of testing Golgi function. BFA blocks the
activation of some ADP-ribosylation factors (ARFs).
 ARFs are small GTPases which regulate vesicular trafficking through the
binding of COPs to endosomes and the Golgi. BFA inhibits the function of
several guanine nucleotide exchange factors (GEFs) that mediate GTP-
binding of ARFs.
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14. AN ANIMAL CELL
Components of a typical animal cell:
1. Nucleolus
2. Nucleus
3. Ribosome (little dots)
4. Vesicle
5. Rough endoplasmic reticulum
6. Golgi apparatus (or "Golgi body")
7. Cytoskeleton
8. Smooth endoplasmic reticulum
9. Mitochondrion
10. Vacuole
11. Cytosol
12. Lysosome
13. Centrosome
14. Cell membrane
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15. AUTHOR’S PAGE
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