Examples of Protein Modifications in the Golgi Apparatus

📚 Quick Study Guide

• 🧬 The Golgi apparatus is an organelle responsible for processing and packaging proteins.
• ⚙️ Protein modifications in the Golgi are post-translational events, occurring after protein synthesis.
• 🍬 Glycosylation, the addition of sugars, is a major modification in the Golgi. Both $N$-linked and $O$-linked glycosylation occur.
• ✂️ Proteolytic cleavage, or cutting proteins, can activate or inactivate them.
• 🧪 Phosphorylation, the addition of phosphate groups, can regulate protein activity.
• 📦 Sulfation, the addition of sulfate groups, occurs on tyrosine residues and carbohydrates.
• 📍 Acylation, the addition of acyl groups, can target proteins to membranes.

🧪 Practice Quiz

1. Which of the following is a major type of protein modification that occurs in the Golgi apparatus?
   1. Ubiquitination
   2. Glycosylation
   3. SUMOylation
   4. Lipidation
2. What type of glycosylation starts in the ER and is further modified in the Golgi?
   1. $O$-linked glycosylation
   2. $C$-mannosylation
   3. $N$-linked glycosylation
   4. Glypiation
3. Proteolytic cleavage in the Golgi is often involved in:
   1. Protein degradation
   2. Protein folding
   3. Protein activation
   4. Protein aggregation
4. Phosphorylation in the Golgi typically occurs on which amino acid residues?
   1. Alanine, Valine, Leucine
   2. Serine, Threonine, Tyrosine
   3. Glycine, Proline, Isoleucine
   4. Aspartic acid, Glutamic acid, Lysine
5. Sulfation in the Golgi primarily occurs on:
   1. Lysine residues
   2. Arginine residues
   3. Tyrosine residues and carbohydrates
   4. Histidine residues
6. Acylation, such as palmitoylation, often targets proteins to:
   1. The nucleus
   2. The mitochondria
   3. The plasma membrane
   4. The endoplasmic reticulum
7. Which of the following modifications does NOT typically occur in the Golgi apparatus?
   1. Glycosylation
   2. Phosphorylation
   3. Myristoylation
   4. Sulfation