Chapter 6 Flashcards
plasma membrane
thin layer of lipids and proteins that separates the cell in its surroundings
bilayer
layer two molecules thick
cholesterol
predominant sterol in animal cells membranes
transport proteins
form channels that allow selected polar molecules and ions to pass through membrane
recognition proteins
identify a cell as part of the individual or foreign
receptor proteins
bind cells close together by recognizing and binding receptors or chemical groups on other cells or the ecm
glycolipids
lipid molecules with carbohydrate group attached
glycoproteins
carbohydrates being attached to protein in exterior facing lipid layer
glycocalyx
surface coat on cell membrane made of glycolipids and glycoproteins
fluid mosaic model
membrane consists of fluid phospholipid bilayer where proteins are embedded and float freely
integral proteins
proteins embedded in phospholipid layer
peripheral protenis
held to membrane by noncovalent bonds formed with polar parts of integral proteins or membrane lipids
freeze fracture technique
freezing a group of cells and then breaking the frozen piece to see the inside
transport
controlled movement of ions and molecules from one side of the membrane to another
passive-high to love
active-low to high
difficusion
net movement from high conc to low conc
concentration gradient
form of potential energy that drives diffusions
selectively permeable
membranes that allow, impede, or block certain molecule and ions from crossing the membrane
simple diffusion
depends solely on molecular size and lipid solubility
facilitated diffusion
when proteins help polar and charged molecule cross membrane
channel proteins
form hydrphobic channels in membrane that allow water and ions to pass
aquaporins
allow water to pass through membrane
gated channels
can switch between open, closed or intermediates
carrier proteins
bind to a specific solute and transport it across membrane
osmosis
passive transport of water
osmotic pressure
pressure created by the weight of the water of the raised solution balancing the tendency of the water molecules moving in
hypotonic
concentration of cell is higher than surroundings
turgor pressure
pressure pushes cells tightly against their walls to support soft tissue against gravity
hypertonic
concentration inside cell is lower than surroundings
plasmolysis
plant cells shrink and retract cell walls
isotonic
concentration inside and outside cell is equal
membrane potential
active transport of ions may result in a voltage being generated across membrane
primary active transport
protein that transports substance hydrolyzes atp to power itself
secondary active transport
indirectly driven by atp hydrolysis
h+ pump
moves hydrogen atoms across membrane temporarily binding to phosphate group removed from atp during cycle
ca2+ pump
pushes calcium from cytoplasm to cell exterior and from cytosol to vesicles in er
sodium potassium pump
pumps out 3 sodiums and brings in 2 pottasiums created a potential
electrochemical gradient
electrical difference on two sides of membranes
symport co transport
solute moves through membrane channel in same direction as driving ion
antiport exchange diffusion
driving ion moves through membrane in one direction and another molecule moves in the other
bulk phase endocytosis
cell takes in small drop of outside fluid and any molecules with it
coated pit
depression in plasma membrane where receptor proteins go once bound to molecules
clathrin
network of proteins that coat and reinforce cytoplasmic side
phagocytosis
processes of a cell eating a molecule; engulf material and produce large endocytic vesicles
