Transport Mechanism (Passive, Active and Bulk) - Vocabulary Flashcards

Vocabulary flashcards covering passive, active, and bulk transport concepts, tonicity, and related cellular processes from the General Biology 1 notes.

Passive transport

Movement of molecules across a cell membrane without energy input, driven by the concentration gradient (high to low).

Simple diffusion

Diffusion without a helper protein; small, nonpolar molecules (e.g., O2, CO2) move directly through the lipid bilayer.

Diffusion

Movement of particles from regions of higher concentration to lower concentration.

Facilitated diffusion

Diffusion that requires transport proteins (channels or carriers) to move larger or polar molecules (e.g., glucose, ions) across the membrane.

Osmosis

Diffusion of water across a selectively permeable membrane from high water concentration to low water concentration.

Carrier protein

Transmembrane protein that carries specific molecules across the membrane during facilitated diffusion.

Channel protein

Membrane protein that forms pores to allow ions or water to cross during facilitated diffusion.

Semipermeable membrane

Membrane that allows certain molecules to pass while restricting others, essential for osmosis.

Osmotic movement of water

Water moves across a selectively permeable membrane from higher to lower water concentration.

Tonicity

The ability of a solution to affect water movement in or out of cells; determines cellular response to surroundings.

Hypotonic

Solution with lower solute concentration than the cell; water enters the cell (lysis in animals; turgor in plants).

Isotonic

Solution with the same solute concentration as the cell; water enters and leaves at equal rates; cell size remains.

Hypertonic

Solution with higher solute concentration than the cell; water exits the cell (crenation in animals; plasmolysis in plants).

Active transport

Movement of molecules across the membrane against their concentration gradient (low to high) requiring energy (ATP).

ATP

Adenosine triphosphate; energy source used to power pumps in active transport.

Sodium-potassium pump

Active transport pump that moves 3 Na+ out and 2 K+ in, using ATP to maintain electrochemical gradients.

Bulk transport

Movement of large molecules/particles into or out of a cell via vesicles; requires energy.

Endocytosis

Bulk uptake of materials into the cell through vesicle formation.

Phagocytosis

Cell eating; engulfing large particles or cells via endocytosis.

Pinocytosis

Cell drinking; uptake of extracellular fluids via endocytosis.

Receptor-mediated endocytosis

Endocytosis initiated by binding of specific ligands to cell-surface receptors.

Caveolae

Flask-shaped membrane invaginations involved in endocytosis, formed by caveolin.

Clathrin-coated vesicle

Vesicle formed from clathrin-coated pits during certain endocytic pathways.

Caveolin

Protein that forms caveolae in the plasma membrane.

Vesicle

Small membrane-bound sac used to transport substances within or outside the cell.

Phagosome

Vesicle formed around ingested particle during phagocytosis.

Endosome

Vesicle formed after endocytosis that sorts materials inside the cell.

Exocytosis

Release of substances from the cell as vesicles fuse with the plasma membrane.

Nutrient uptake (bulk transport)

Bulk transport enables cells to absorb large molecules (proteins, polysaccharides) via endocytosis.

Waste removal (bulk transport)

Exocytosis expels large wastes and toxins from the cell, maintaining internal health.

Hormone secretion (bulk transport)

Glands release hormones into the bloodstream via vesicle-mediated bulk transport.

Lysis

Bursting of an animal cell due to osmotic swelling in hypotonic solutions.

Crenation

Shrinking of an animal cell due to water loss in hypertonic solutions.

Plasmolysis

Contraction of plant cell cytoplasm away from the cell wall in hypertonic solutions.

Turgor pressure

Pressure within plant cells when vacuoles are hydrated; maintains rigidity in hypotonic environments.