Terms in this set (19)
parts of a membrane
phospholipids, proteins & carbohydrates
selectively (semi-) permeable
allowing some substances to cross a plasma membrane, usually based on size
movement of substances across a plasma membrane (without the addition of energy) from an area of higher concentration to an area of lower concentration (e.g. diffusion, osmosis, facilitated diffusion)
differences in concentration on either side of a membrane; for example, more water molecules on the outside of a plasma membrane than inside
movement of particles across a plasma membrane from an area of high concentration to an area of lower concentration
examples of diffusion
food coloring in water; Febreeze in our classroom, water into the Gummi Bear
movement of substances through a transport protein,(membrane protein) without energy, down the concentration gradient (HI to LOW); type of passive transport
what does facilitated diffusion move?
ions, larger molecules, glucose (small sugars); HI to LOW!!
random movement of water molecules (solvent) across a plasma membrane from an area of high concentration to an area of lower concentration.
movement across the membrane is equal in both directions; solution that has the same water and solute concentration as inside of cell
movement of substances across a plasma membrane with the addition of energy, against (up) the concentration gradient (from an area of lower concentration to an area of higher concentration).
cell engulfs substances that are too large to go through the plasma membrane; requires ATP
cell expels substances that are too large to go through the plasma membrane; requires ATP
an egg in pure water swells, what type of solution is the pure water? Why does the egg swell?
hypotonic; because water diffuses into cell
a relatively low solute concentration outside a cell
hypotonic, cells tend to gain water
putting salt on icy roads in winter. Plants along the road become damaged. What solucion is the salty-water running off from the roads? what happens to the plants?
hypertonic; cells tend to lose water
what is the ideal solution environment for a plant to live in? why?
hypotonic because they need water to constantly enter the plant cells
universal solvent in cells; most of our cells are made of this
concentration gradient is not present; movement of molecules continues equally into and out of the cell