Biology: Diffusion and Osmosis Terminology

Diffusion: Movement of particles from areas of high density to low density, driving the distribution of substances.
Osmosis: A specific type of diffusion focused on water movement across a selectively permeable membrane, affecting cell volume.
Simple Diffusion: Characterized by no energy input or carrier proteins, allowing small nonpolar molecules to pass through membranes easily.

Facilitated Diffusion: Involves specific proteins that create channels in the cell membrane for certain molecules, enabling their movement without energy.
Active Transport: Contrasts passive processes by utilizing ATP to move substances against their concentration gradient, crucial for nutrient uptake.

Concentration Gradient: The difference in concentration of a substance between two locations, influencing movement direction during diffusion.
Hypertonic Solutions: Have a higher solute concentration compared to another solution, leading to water movement out of cells.
Hypotonic Solutions: Feature a lower solute concentration, potentially causing cells to swell as water flows in.
Isotonic Solutions: Maintain equal solute concentration compared to another solution, resulting in no net movement of water.

Protein Pore: Specialized channels that permit larger molecules to traverse the cell membrane, essential for cellular function.
Hydrophilic Head: Refers to the water-attracting aspect of phospholipids in the cell membrane, facilitating interactions with the aqueous environment.
Hydrophobic Tail: Describes the water-repelling portion of phospholipids, forming a barrier important for membrane integrity.

ATP (Adenosine Triphosphate): The energy currency required for active transport processes, enabling cells to maintain homeostasis.
Cell Membrane: A selectively permeable barrier regulating which molecules enter or exit a cell, crucial for maintaining cellular function and environment.