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30 terms

AP Biology Chapter 6 (Raven Johnson Losos Singer)

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Plasma Membrane
delicate skin of liquids with embedded protein molecules (allows non-water soluble substances to pass in and out of the cell)
Phospholipids
the molecules that form the foundation of a cell's membrane (form the lipid layer), polar heads, non polar tails, one head, two tails
Phospholipid bilayer
When many phospholipids are grouped together in water, they find pairs so they can push their hydrophobic tails together and orients their polar head toward the outside. When a layer forms it is called a phospholipid bilayer.
Fluid Mosaic Model
the model of membranes proposed in 1972 by Singer and Nicolson suggesting the globular proteins that allow substances to pass in and out of the membrane do not sandwich the phospholipid bilayer but are placed in it randomly (like a mosaic) with the non polar parts lining up with the tails of the phospholipids and the polar ends sticking out
Transmembrane Proteins
proteins in the phospholipid bilayer that float around and provide passageways. THEY FLOAT. there is a variety in the membrane. they differ in the way that they traverse (float)
Diffusion
when molecules move from where their concentration is high to where it is low
Selectively Permeable
Only an exact molecule can pass through it's protein
Ion Channels
posses a hydrated interior that span the membrane. ions react well with polar things because they are charged but cannot move between cytoplasm and extracellular fluid so these give passage
Carriers
class of membrane proteins that transport ions as well as other solutes such as sugars and amino acids across the plasma membrane. facilitate the movement by physically binding to them and then releasing on the other side of the membrane.
Facilitated Diffusion
the process where solutes move from highest to lowest concentration gradient but do so with the help of carriers
Solvent
water
Solutes
things that dissolve in water
Aquaporins
specialized channels for water that facilitate water flow
osmosis
net water movement across a membrane toward a higher solute concentration by diffusion
Osmotic Concentration
concentration of ALL solutes in a solution
Hyperosmotic
when one solution has a higher concentration of the solution, (a higher osmotic concentration)
hypoosmotic
the solution with the lower osmotic concentration
isosmotic
when two solutions have the same osmotic concentration
hydrostatic pressure
pressure of the cytoplasm pushing against the cell membrane when water diffuses into the cell (when cytoplasm is hypertonic)
Osmotic Pressure
the pressure that must be applied to stop the osmotic movement of water across a membrane
Turgor Pressure
hydrostatic pressure in a plant cell pushing the plasma membrane against the cell wall making the cell rigid
Endocytosis
when the plasma membrane envelopes food particles.
Phagocytosis
the material the cell takes in is made up of particles
Pinocytosis
the material the cell takes in is liquid
Receptor Medicated Endoctosis
when specific molecules are transported into eukaryotic cells (grabbed by receptors)
Exocytosis
discharge of material from vesicles of the cell surface
Active Transport
with the help of ATP solutes are moved UP their concentration gradient
Sodium-Potassium Pump
pumps Na+ out and K+ in
Countertransport
when another substance is moved outward such as Ca++ or H+ when the Na+ is moved inward
Antiport
what Na+ and another substance bind to (on either end) then are exchanged