Golgi Apparatus

1. Golgi Apparatus By Kirsten Lydon

2. What is a Golgi apparatus? • Sometimes called a Golgi body • A flattened stack of membranes that form a complex structure • Individual stacks are called cisternae • Latin for “collecting vessels” • Cisternae vary in number • 1 to a few in protists • 20 or more in animal cells • Several hundred in plant cells

3. Artist’s depiction Real life image

4. What does it do? • Functions include the collection, packaging, distribution, and modification of molecules • These molecules are synthesized in one location of the cell and are used in another. • Some may leave the cell through the cellular membrane • Like the mailroom of the cell A vesicle transporting proteins out of the cell

5. What does it do? (cont.) • Proteins and lipids made on the rough and smooth endoplasmic reticulum (ER) are modified as they pass through the Golgi apparatus • ex. The addition or modification of short sugar chains which make: • Glycoproteins and glycolipids • It also synthesizes cell wall components • Noncellulose polysaccharides that form the cell wall of plants are synthesized in the Golgi body. • Afterwards, they are sent to the plasma membrane and are added to cellulose which assembles the exterior of the cell.

6. The Golgi doing different jobs

7. It has a front and back • The front is called the cis face • Usually found near the ER • Materials enter the Golgi body in transport vesicles that come from the ER • Lumen • Cavity where proteins, to be secreted by the cell, are packaged in vesicles to be released • The back is called the trans face • Materials are discharged from this face in secretory vesicles • Lysosomes • Come from the Golgi apparatus • Contain a high level of degrading enzymes

8. How does it move materials? • It is proposed that material moves through the cell by means of: • cisternal maturation • Transport of vesicles between cisternae • And direct tubular connections • The primary accepted method of transport is cisternal maturation • When individual cisternae mature from early cis to late trans • Because the cisternae are so tightly stacked together it is hard to give a definitive answer as to how transport actually occurs.

9. Protein transport through endomembrane system

10. Connected to Alzheimer's disease • It is an irreversible, progressive brain disease that slowly destroys memory and thinking skills. • Causes dementia and eventually death • In Alzheimer’s disease, the Golgi bodies seem to fall apart or become fragmented as it progresses.