Membrane Structure and Transport

Flashcards covering key concepts about membrane structure and transport mechanisms.

What are the main components of cell membranes?

Phospholipids, membrane proteins, and carbohydrates.

What is the structure of a phospholipid?

Glycerol + 2 fatty acid tails (hydrophobic) + phosphate group (hydrophilic).

What model describes the arrangement and movement of membrane components?

Fluid Mosaic Model.

What is passive transport?

Transport that does not require metabolic energy (ATP) and includes simple diffusion, osmosis, and facilitated diffusion.

What is dynamic equilibrium?

A state where no net movement occurs at equilibrium, although individual molecules continue to move.

What defines osmosis?

The diffusion of water across a selectively permeable membrane.

What is tonicity?

The ability of a solution to cause a cell to gain or lose water.

What are isotonic, hypertonic, and hypotonic solutions?

Isotonic: solute concentration equal inside and outside; Hypertonic: solute concentration higher outside than inside; Hypotonic: solute concentration lower outside than inside.

What is facilitated diffusion?

Passive transport through a transport protein that does not require ATP.

What is active transport?

Transport that requires ATP and moves substances against their concentration gradient.

Describe bulk transport.

A type of active transport that uses vesicles to transport many molecules at once without crossing through the bilayer.

What is exocytosis?

The process where a vesicle fuses with the plasma membrane, releasing its contents outside the cell.

What is endocytosis?

The process where materials are taken in by folding the plasma membrane inward to form a vesicle.

What are the types of endocytosis?

Phagocytosis (large food particles) and pinocytosis (fluids and dissolved molecules).