Biology Chapter 7
isotonic
equal amounts of solute molecules
why is a membrane structure model called a fluid mosaic?
the membrane is fluid and has motion
cholesterol
structure that allows cells to communicate with each other to work as a unit
phospholipid bilayer
structure that consists of two layers of lipids
transport protein
structure that helps move molecules across the cell membrane
carbohydrate chain
structure that identifies the cell / recognizes stuff around the cell
solute
substance that is dissolved
portion of the bilayer that is hydrophobic
tails
concentration
the amount of molecules in a specified area
concentration gradient
a difference in amount of molecules between two areas
carrier molecule
a protein that functions in transport of molecules across a membrane
selectively permeable
allows certain molecules to pass through; keeps some molecules out
solvent
fluid that dissolves a solid, liquid, or gas
hypotonic
having less solute molecules than cytoplasm of a cell / having a lower concentration of solute than another solution
hypertonic
having more solute molecules than a cytoplasm of a cell / having a higher concentration of solute than another solution
portion of the bilayer that is hydrophilic
heads
facilitated diffusion
high concentration to low concentration movement of monomers; uses transport protein; no energy required
osmosis
high concentration to low concentration movement of water; through phospholipid bilayer; no energy required / diffusion of molecules through a semipermeable membrane from a place of higher concentration to a place of lower concentration
passive transport
movement of molecules from high concentration to low concentration; no energy required
active transport
movement of molecules from low to high; uses transport protein; requires energy /energy-requiring process that moves material across a cell membrane against a concentration difference
diffusion
movement of particles from an area of high concentration to an area of lower concentration
function of protein molecules in membrane
moves large particles in, through, and out of the cell membrane
solution
mix of a substance that is dissolved in another
Na/K pump
active process; moves 3 NA+ions out of the cell and 2K+ions into the cell against concentration gradient
what does active transport need?
energy ATP which requires carrier protein
two major components of the cell membrane
proteins and lipids
endocytosis
use of vesicles to move polymers into the cell
exocytosis
use of vesicles to move polymers out of the cell
hydrophobic
water-fearing
hydrophilic
water-loving
when does the movement of materials in and out of the cell NOT require energy?
when the molecules are moving with the concentration gradient
turgor pressure
outward pressure on cell / the pressure that water molecules exert against the cell wall
overall structure of the cell membrane
phospholipid bilayer
membrane structure consists of
phospholipid bilayer, carrier proteins, and pore proteins
the 4 responsibilities of the cell membrane
protects and encloses the cell, gives shape, allows transportations in and out, and carries out metabolic reactions
three ways the rate of diffusion can be affected
solid, liquid, gases; temperature; concentration gradient
