Transport across The Plasma Membrane Flashcards
What is diffusion?
The movement of substances from an area of higher concentration to an area of lower concentration until equilibrium is reached. At equilibrium the concentration is the same throughout the solution.
What is osmosis?
Osmosis is the movement of water molecules through a selectively permeable membrane from an area of higher water concentration to an area of lower water concentration
What is the passive process?
Movement of substances down a concentration gradient until equilibrium is reached: do not require cellular energy in the form of ATP.
Movement of a substance by kinetic energy y down a concentration gradient until equilibrium is reached.
What is facilitated diffusion?
Passive movement of a substance down its concentrationgradent aided by ion channels and carriers
What is the active process?
Movement of substances against a concentration gradient; requires cellular energy in the form of ATP
What is active transport?
Transport in which cell expands energy to move a substance across the membrane against its concentration gradient aided by membrane proteins that act as pumps; these integral membrane proteins use energy supplied by ATP
What substances are transported in active transport?
Na+, K+, Ca2+, H+, I-, Cl- and other ions
What is transport in vesicles?
Movement of substances into or outof a cell in vesicles that bud from the plasma membrane; requires energy supplied by ATP
What is endocytosis?
Movement of substances into a cell in vesicles
What is phagocytosis?
“cell eating”; movement of a sold particle into a cell after pseudopods engulf it
What is bulk-phase endocylosis?
“Cell drinking”; movement of extracellular grid into a cell by infolding of plasma membrane
What is exocytosis?
Movement of substances out of a cell in secretory vesicles that fuse with the plasma membrane and release their contents into the extracellular fluid
What substances are transported in phagocytosis?
Bactena, viruses, and aged or dead cells
What substances are transported in bulk-phase endocytosis?
Solutes in extracellular fluid
What substances are transported in exocytosis?
Neurotransmitters, hormones and digestive enzymes
