🧫 Cell Biology — Intermediate#

Scope — Membrane dynamics, intracellular trafficking, cytoskeleton, cell cycle basics.

Key concepts#

• Membrane transport — passive diffusion, facilitated diffusion, active transport, endocytosis, exocytosis.
• Cytoskeleton — microfilaments, microtubules, intermediate filaments; roles in shape and transport.
• Cell cycle — G1, S, G2, M phases; checkpoints and basic regulation.

Seed Q&A triads#

• Q: What mechanisms move vesicles along the cytoskeleton?
  A: Motor proteins (kinesin, dynein, myosin) transport vesicles along microtubules or actin filaments.

• Q: How does receptor-mediated endocytosis differ from pinocytosis?
  A: Receptor-mediated endocytosis is selective via ligand–receptor binding; pinocytosis nonspecifically engulfs extracellular fluid.

• Q: What triggers the G1/S checkpoint?
  A: Sufficient cell size, nutrient availability, and growth factor signaling; cyclin/CDK activity integrates these signals.

Short exercises#

• Predict effects of microtubule destabilizers on intracellular transport and mitosis.