AP Biology Questions: Epithelial Tissue and Cell Junctions

📚 Quick Study Guide

• 🔬 Epithelial Tissue: Covers body surfaces and lines body cavities and organs. Functions include protection, absorption, filtration, excretion, secretion, and sensory reception.
• 🧱 Cell Junctions: Structures that connect cells to each other and to the extracellular matrix.
• 🤝 Tight Junctions: Seal cells together in an epithelial sheet, preventing leakage of molecules between them.
• ⚓️ Adherens Junctions: Join actin bundles in one cell to a similar bundle in a neighboring cell. Cadherins are key proteins.
• 💪 Desmosomes: Join intermediate filaments in one cell to those in a neighbor. Provide strong adhesion.
• 🕳️ Gap Junctions: Allow small molecules to pass directly from cell to cell. Formed by connexons.
• 🌱 Hemidesmosomes: Anchor epithelial cells to the basement membrane. Integrins are key proteins.

🧪 Practice Quiz

1. Which type of cell junction prevents the passage of molecules between epithelial cells?
   1. A) Adherens Junction
   2. B) Gap Junction
   3. C) Tight Junction
   4. D) Desmosome
2. What protein is primarily associated with adherens junctions?
   1. A) Connexin
   2. B) Integrin
   3. C) Cadherin
   4. D) Keratin
3. Which cell junction allows direct communication between adjacent cells via small molecules?
   1. A) Tight Junction
   2. B) Desmosome
   3. C) Gap Junction
   4. D) Hemidesmosome
4. What is the main function of desmosomes?
   1. A) To prevent leakage of molecules
   2. B) To provide strong adhesion
   3. C) To allow cell communication
   4. D) To anchor cells to the basement membrane
5. Which type of junction anchors epithelial cells to the basement membrane?
   1. A) Adherens Junction
   2. B) Desmosome
   3. C) Tight Junction
   4. D) Hemidesmosome
6. What protein is associated with hemidesmosomes?
   1. A) Cadherin
   2. B) Connexin
   3. C) Integrin
   4. D) Occludin
7. Which of the following is NOT a function of epithelial tissue?
   1. A) Absorption
   2. B) Contraction
   3. C) Secretion
   4. D) Protection