Membrane Transport Flashcards
(22 cards)
Osmosis
The diffusion of the SOLVENT across a semi-permeable membrane separating two solutions
PASSIVE
Diffusion
The movement of molecules from a region where they are more concentrated to one where they are less concentrated
PASSIVE
Facilitated diffusion
Molecules are helped across the membrane by transport/ carrier proteins (with the concentration gradient) PASSIVE
Active transport
Protein aided transport against the concentration gradient
Bulk transport
Endocytosis (into cell):
phagocytosis
pinocytosis
receptor assisted endocytosis
Exocytosis (out of cell)Hypertonic
High solute
Low solvent
Hypotonic
Low solute
High solvent
Isotonic
Equal solute and solvent
Materials naturally move from…
…high to low concentrations
Homeostasis
The steady state that results from maintaining near-constant conditions on the internal environment of a living thing. The cell membrane is responsible for homeostasis.
Isotonic
When the water concentration inside the cell equals the water concentration outside the cell, equal amounts of water move in and out of the cell
Hypotonic
When the water concentration outside the cell is greater that that inside the cell, water moves into the cell
Cell may burst (lysis)
Hypertonic
When the water concentration inside the cell is greater than that outside the cell, water moves out of the cell
Facilitated diffusion
PASSIVE TRANSPORT
carrier proteins recognize and help to move dissolved molecules across the cell membrane
Channel protein
A tunnel like shape that allows charged particles to pass through the lipid bilayer
Active transport
The process of moving substances against their concentration gradients (uses energy)
Active transport pump
The pump:
drives the system runs on energy from cell metabolism
Actively pumps ions across the cell membrane against concentration gradients
Is a cell membrane protein
Endocytosis
When the cell membrane folds inward, trapping and enclosing a small amount of matter from the extracellular fluid
Pinocytosis
The intake of a small droplet of extracellular fluid, with any dissolved substances or tiny particles it contains. Cell drinking.
Phagocytosis
The intake of a large droplet of extracellular fluid, often including particulate matter. (Cell eating)
Receptor assisted endocytosis
The intake of specific molecules that attach to special proteins in the cell membrane that serve as receptors. Cholesterol.
Exocytosis
Reverse of endocytosis
A vesicle from inside the cell moves to the cell surface. The vesicle membrane fuses to the cell membrane and the contents of the vesicle is secreted into the extracellular fluid
Important in cells that secrete stuff like pancreatic cells that secrete insulin
