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A Handbook of Biology

Golgi apparatus

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Densely stained reticular structures near the nucleus.

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First observed by Camillo Golgi (1898).

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They consist of flat, disc- shaped sacs (cisternae) of 0.5– 1.0 mm

diameter.

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Cisternae are concentrically arranged with convex cis (forming) face

and concave trans (maturing) face. Cis & trans faces are totally different,

but interconnected.

Function of Golgi apparatus:

Shipping

side of Golgi apparatus

Trans face

Newly forming vesicle

Secretary vesicle

Receiving

side of Golgi apparatus

Cis face

Lumen

Cisternae

Secretes packed materials

to intra-cellular targets or

outside the cell.

(NEET 2018)

Materials to be packaged

as vesicles from the ER fuse

with the cis face and move

towards the trans face.

This is why Golgi apparatus

remains in close association

with the endoplasmic

reticulum.

Proteins synthesized by ribosomes on the ER are modified in the

cisternae of Golgi apparatus before they are released from its trans

face.

Formation of glycoproteins and glycolipids.

(AIPMT 2011)

Lysosomes

These are membrane bound vesicular structures formed by the

process of packaging in the Golgi apparatus. (NEET 2019)

Lysosomal vesicles contain almost all types of hydrolytic enzymes

(hydrolases– lipases, proteases, carbohydrases). They are active

at acidic pH. They digest carbohydrates, proteins, lipids and nucleic

acids