Bio Ch. 4 (part 2) Membrane Transport Flashcards
Phospholipid bilayer
The framework of the cell membrane
Phospholipids are ________ molecules
Amphipathic
Hydrophobic tails
(water-fearing) region faces inward
Hydrophilic heads
(water-loving) region faces outward
Phospholipids
main components of the cell membrane
Proteins
Add function, such as, transport, enzymes, attachment, & communication
Carbohydrates
Cell to Cell recognition site (like lock and key)
Cholesterol
Only found in animal plasma membranes, Strengthens the plasma membrane
“Mixed composition
several molecule are embedded or attached
Membranes are ________
semifluid
________ are relatively weak
Not bonded to each other
Phospholipids
The plasma membrane is _______ _______
Selectively permeable
Passive transport requires __ ______
NO ENERGY (no ATP)
Does simple diffusion required membrane proteins?
No
Do facilitated diffusion require the diffusion of solutes through transport proteins in the plasma membrane.
Yes
Active Transport requires ______
Energy (ATP)
Exocytosis
Material inside the cell packaged into vesicles and Expelled into the extracellular fluid (outside the cell)
Endocytosis
Plasma membrane invaginates (folds inward) to form a vesicle that brings substances (extracellular fluid) into the cell
Phagocytotic
White blood cell engulfing bacteria
Osmosis
Diffusion of water across a selectively permeable membrane
Tonicity
Occurs in response to a difference in solute concentration between the fluids on either side of the membrane
Isotonic
Equal concentrations of solute and water; no osmosis
Hypertonic
Concentration of solutes greater outside the cell than inside the cell; water flows out
Hypotonic
Concentration of solute greater inside the cell than outside the cell; water flows in
