Chapter 6 Flashcards
Active Transport
moving substances against the concentration/electrical gradient. Requires cellular energy, driven by ATP hydrolysis, requires a membrane protein, and is specific
Antiporter
moving two substances in opposite directions
Aquaporin
special channels that allow water to cross membranes
Carrier proteins
membrane proteins that bind substances and speed their diffusion through the bilayer
cell adhesion
strengthening of the connection between two cells
cell junctions
specialized structures that hold cells together
cell recognition
cells recognize each other and bind to another cell of a certain type
concentration gradient
difference in concentration between two sides of a cell membrane
channel proteins
integral membrane proteins that form a tunnel
desmosome
“spot welds” (materials move around in extracellular matrix)
endocytosis
brings molecules together in eukaryotic cells (cell eating)
diffusion
random movement to equalibrium
fluid mosaic model
describes general structure of biological membranes
exocytosis
materials in vesicles are expelled from the cell
facilitated diffusion
passive movement of polar molecules through a membrane, no energy required, driven by concentration gradient, requires a membrane protein, and is specific
gated channel
can be closed or
open to ion passage
gap junctions
allow communication
glycolipid
carb+lipid
Hypertonic
high solute concentration
homotypic
same molecule sticks out from
both cells and bind to each other
heterotypic
cells have different proteins that
bind together
glycoprotein
carb+protein
Hypotonic
low solute concentration
integrin
proteins that help cells attach to each other and to the ECM
ion channel
channel proteins with hydrophilic
pores
integral membrane proteins
have hydrophobic and hydrophilic
regions; some extend across
bilayer, others partially
embedded
isotonic
equal solute concentration
peripheral membrane proteins
lack hydrophobic regions so do
not penetrate bilayer
ligand
a molecule that can bind to a receptor
passive transport
no energy required
phagocytosis
molecules or entire cells are engulfed
pinocytosis
vesicle forms to bring small dissolved substances or
fluids into a cell
primary active transport
requires direct hydrolysis of ATP
receptor protein
integral membrane proteins located at specific sites on cell membrane; sites coated with other proteins
receptor mediated endocytosis
very specific; macromolecules
bind to receptor proteins
secondary active transport
energy comes from ion
concentration gradient established by primary active transport
selective permeability
only some things enter and exit the cell membrane
simple diffusion
small molecules pass through lipid
bilayer, no energy required, driven by concentration gradient, no membrane protein required, not specific
sodium potassium pump
found in animal cells; an integral membrane glycoprotein (an antiporter)
symporter
moving two substances in the same direction
tight junction
prevent substances from moving through spaces between cells; help ensure directional movement
of materials
transmembrane domains
on inner or outer side of bilayer,
have specific functions
transmembrane proteins
extend all the way through
phospholipid bilayer, contain one or more transmembrane
domains
turgor pressure
plant cells with rigid cell walls build up internal pressure that keeps more water from entering
uniporter
moves one substance in one direction
