Objective Two Part D: Bulk Transport

Overview

• Bulk transport involves moving large particles across the cell membrane.
• Distinct from passive transport (osmosis, facilitated diffusion, simple diffusion).
• Requires energy in the form of ATP.

Vesicular Transport

• Necessary for transferring large particles that cannot pass through a protein channel.
• Particles are delivered by vesicles.
• Vesicle fuses with the membrane to release contents to the extracellular fluid.

Types of Vesicular Transport

1. Endocytosis

   • Moving materials into the cell.
   • Subcategories:
     • Phagocytosis ("cell eating")
       • Involves intake of large particles.
       • Example: White blood cell engulfing a bacteria.
     • Pinocytosis ("cell drinking")
       • Involves intake of extracellular fluid and dissolved solutes (e.g., sodium ions, sugars).

2. Exocytosis

   • Moving materials out of the cell.
   • Vesicles transport proteins or macromolecules from the Golgi apparatus to the cell membrane.
   • Example: Proteins synthesized by ribosomes are exported out of the cell.

Key Points

• Bulk transport is an active process requiring ATP.
• Endocytosis and exocytosis are crucial for cellular intake and export of materials.
• Videos and diagrams can provide a visual understanding of these processes.