Membrane Transport Flashcards
Diffusion Facilitated Diffusion Osmosis
What is the process of passive transport?
(-ΔG) spontaneous
Movement of molecules down a concentration gradient that does NOT require energy.
(high concentration → low concentration)
What are the three different types of passive transport?
- simple diffusion
- facilitated diffusion (requires a carrier or channel protein)
- osmosis (water)
What is the process of active transport?
(+ΔG) nonspontaneous
Movement of molecules against a concentration gradient that requires energy.
(low concentration → high concentration)
What is the difference between primary active transport and secondary active transport?
Primary active transport: uses ATP
Secondary active transport: uses ATP and an electrochemical gradient
- antiport-opposite direction
- symport-same direction
Which kind of molecules diffuse easily through the plasma membrane?
Small, nonpolar and uncharged molecules.
What is a hypotonic solution?
Less solutes in solution (on the outside of the cell) than inside of the cell.
“cell bursts”
What is a hypertonic solution?
More solutes in solution (on the outside of the cell) than inside of the cell.
“cell lyses”
What is an isotonic solution?
Equal amounts of solute inside the cell and outside of the cell (in solution).
[Mnemonic]
“Hypo“tonic: “little of”/low
“Hyper“tonic: “lots of”/high
(how to differentiate between hypotonic and hypertonic)
“Hypo“tonic: “little of”/low
“Hyper“tonic: “lots of”/high
(Think of a hyperactive person. They have “high” energy.)
Solutes cannot cross the cell membrane but water can. But when water is surrounded by solutes whether inside of the cell or in solution, water cannot move (it is obstructed).
If a cell is hypertonic with respect to its medium/solution, what will happen to the cell?
The cell will swell because the solution is hypotonic.
The water in the cell is obstructed by the high conc. of solutes in the cell. But the water in solution is NOT obstructed due to the low conc. of solutes in the solution. Therefore the water in solution can move and enter the cell, causing it to swell.
If a cell is hypotonic with respect to its medium/solution, what will happen to the cell?
The cell will lyse/__shrink because the solution is hypertonic.
The water in solution is obstructed due to the high conc. of solutes in the solution. But the water in the cell is NOT obstructed due to the low conc. of solutes in the cell. Therefore the water in the cell can move and exit the cell, causing it to lyse.
What is osmotic (or oncotic) pressure?
Pressure that must be applied to STOP osmosis.
Osmotic pressure is a colligative property because it is dependent on the number of solutes not the type.
What is the equation for osmotic pressure?
