midterm 1 (cell) Flashcards
cytoplasm
cytosol + organelles
organelles
organs of the cell
plasma membrane
tiny amphipathic membrane of lipids and proteins that contains the cytoplasm
amphipathic
both hydrophilic and hydrophobic parts
integral proteins
permanently attached to the membrane. can be transmembrane proteins or peripheral proteins
transmembrane protein
type of integral membrane that goes through the entire membrane
peripheral protein
type of integral membrane that is attached to the polar heads of the phospholipid bilayer (inside or outside of the cell), but they do not cross the membrane. helps support membrane
glycocalyx
sugary coating of cell membrane that allows for adherence to other tissues and acts as a cellular signature for recognition (white blood cells can recognize foregin cell)
characteristics of cell membrane
- membrane fluidity (from double bonds/kinks in the fatty acid tails)
- membrane permeability (selectively permeable)
- membrane gradients
diffusion
type of passive transport where molecules (both solvent and solute) move from high to low concentration
simple diffusion
non polar, hydrophobic substances move through the cell membrane (O2, CO2, nitrogen gases, vitamins DEAK)
facilitated diffusion
passive transport of molecules that are too polar or highly charged through cell membrane with help from specific transmembrane integral proteins
channel-mediated diffusion
integral protein ion channel allows for passage of specific small, hydrophilic, inorganic ions into a cell
carrier-mediated diffusion
passive transport of substances (glucose, galactose, fructose, vitamins) into the cell via carrier/transporter proteins. there is a transport maximum.
osmosis
net movement of a SOLVENT through a selectively permeable membrane via aquaporins. solvent moves from higher H2O concentrations to an area of lower H2O concentration, which equalizes the concentrations on either side of the membrane
hydrostatic pressure
pressure exerted by fluid at equilibrium due to the force of gravity. (equilibrium when there is an equal amount of H2O particles on either side of the membrane)
osmotic pressure
the pressure needed to be applied to a solute to prevent the solvent from passing through the membrane by osmosis. how much you need to push against membrane to stop H2O from coming back through
active transport
movement of polar and charged solutes AGAINST their concentration gradient. requires ATP energy and has a transport maximum.
primary active transport
pumps substance across plasma membrane against concentration gradient. Na+/K+ pump (Na+ out, K+ in)
secondary active transport
energy stored in Na+/H+ concentration gradients is used to drive other substances across membrane against their own concentration gradient (like holding the door open for someone)
antiporter
integral membrane protein involved in secondary active transport that carries 2 or more molecules in OPPOSITE directions through the cell membrane
symporter
integral membrane protein involved in secondary active transport that carries 2 or more molecules in the SAME direction through the cell membrane
endocytosis
active transport INTO the cell via a vesicle. can be receptor mediated, phagocytosis, or pinocytosis
exocytosis
active transport OUT of the cell within a vesicle. secretory vesicles from inside cell fuse with plasma membrane and release contents into extracellular fluid.