Examples of Nuclear Pores and Their Function

📚 Quick Study Guide

• 🧬 Nuclear Pore Complex (NPC): Large protein complex embedded in the nuclear envelope.
• 🚪 Function: Regulates the transport of molecules between the nucleus and the cytoplasm.
• 📏 Size: About 120 nm in diameter.
• 🧩 Structure: Composed of approximately 30 different nucleoporins (Nups).
• ➡️ Import: Proteins and RNA molecules are transported into the nucleus.
• ⬅️ Export: mRNA, tRNA, and ribosomes are transported out of the nucleus.
• 🔑 Mechanism: Small molecules can passively diffuse, while larger molecules require active transport mediated by transport receptors (e.g., importins and exportins).
• ⚡ Energy: Active transport requires energy, typically in the form of GTP hydrolysis.

Practice Quiz

1. Which of the following is the primary function of nuclear pores?
   1. A. Protein synthesis
   2. B. DNA replication
   3. C. Regulating transport between the nucleus and cytoplasm
   4. D. Lipid metabolism
2. What are the protein subunits that make up the nuclear pore complex called?
   1. A. Histones
   2. B. Nucleoporins (Nups)
   3. C. Lamins
   4. D. Actins
3. Which type of molecule is typically exported from the nucleus to the cytoplasm through nuclear pores?
   1. A. DNA
   2. B. mRNA
   3. C. Histones
   4. D. Lipids
4. Which process BEST describes how small molecules move through nuclear pores?
   1. A. Active Transport
   2. B. Passive Diffusion
   3. C. Facilitated Diffusion
   4. D. Endocytosis
5. Which of the following is required for active transport through the nuclear pore?
   1. A. ATP hydrolysis
   2. B. GTP hydrolysis
   3. C. Protein folding
   4. D. Lipid synthesis
6. What is the approximate diameter of a nuclear pore?
   1. A. 12 nm
   2. B. 120 nm
   3. C. 1.2 μm
   4. D. 12 μm
7. Which of the following proteins mediates the transport of molecules into the nucleus?
   1. A. Exportins
   2. B. Importins
   3. C. Kinesins
   4. D. Dyneins