biology: cell structure and function, cell movement

peripheral proteins

bound to the surface of the membrane

psuedopodia

packages particles into food vacuole, which fuses to lysosome to be digested, cell surrounds particles with this

high temp cholestrol

reduces movement

mosiac

to be comprised of many macromolecules

membrane carbohydrates

interact with the surface molecules of other cells, facilitating cell-cell recognition

glycoproteins

proteins that have carbohydrates covalently bonded to them

plants contransport

uses sugar and amino acids

phagocytosis

cell engulfs particles to be digested by lysosomes (cell eating)

pintocytosis

cell takes in dissolved molecules in a protein coated vesicle, to mediate

receptor mediated endocytosis

specific uptake of molecules via solute binding to receptors on plasma membrane. allows cell to take up large quantities of a specific substance

tonicity

ability of an extracellular solution to cause a cell to gain or loose water

hypertonic

having a higher concentration of solute than another solution.

cholesterol

helps maintain fluidity of a cell

low temp cholestrol

increases movement, reduces tight packing of phospholipids

membrane proteins

integral proteins and peripheral proteins

integral proteins

embedded in the hydrophobic interior of the lipid bilayer

glycolipids

carbohydrates covalently bonded to lipids

selective permeability

condition or quality of allowing some, but not all, materials to cross a barrier or membrane

Easy passage across the membrane

small, non polar, hydrophobic molecules
-ex: hydrocarbons, CO2, O2, N2

difficult passage across the membrane

hydrophilic, polar molecules, large molecules, ions

passive transport

the movement of substances across a cell membrane without the use of energy by the cell

concentration gradient

A region along which the density of a chemical substance increases or decreases.

diffusion

substances move from high to low concentration, down concentration gradient

active transport

the movement of ions or molecules across a cell membrane into a region of higher concentration, assisted by enzymes and requiring energy/ATP

proton pump

active transport protein that transport hydrogen ions out of a cell against their concentration gradient, generating a membrane potential in the process, mostly H+ cells

contransport

uses energy stored in electrochemical gradients (generated by pumps) to move substances against concentration gradient

favorable movement

downhill diffusion

unfavorable movement

uphill diffusion

exocytosis

secretion of materials via vesicles, which cam fuse to membrane via a bilayer, released to extracellular fluid

endocytosis

uptake of molecules from vesicles fused from plasma membrane

osmosis

diffusion of water through a selectively permeable membrane

osmoregulation

regulation of solute concentrations and water balance by a cell or organism

isotonic

when the concentration of two solutions is the same

hyptonic

having a lower concentration of solute than another solution