Cell Transport Mechanisms Flashcards
What goes in the cell membrane
carbohydrates, sugars, proteins, amino acids, Lipids, salts, O2, H2O
What goes out the cell membrane
ammonia, salts, CO2, H2O
Movement of molecules across the cell membrane
cell transport
a process by which an ion or molecule passes through a membrane along a concentration gradient, or from an area of high concentration to an area of low concentration. It’s like moving from the train to the platform of a subway station or stepping out of a crowded room. Basically, it gives an ion or molecule “room to breathe.”
- no energy required
passive transport
Why does passive transport have no energy required
because of its intrinsic/natural energy called thermal motion
types of passive transport
simple diffusion, facilitated diffusion, osmosis
type of passive transport wherein the movement of molecules through the membrane from a region of high concentration to a low concentration
- no transport protein used
- net diffusion/net flow - equilibrium
- At equilibrium, the movement of molecules does not stop. At equilibrium, there is an equal movement of materials in both directions. (it just stops going to the other area)
simple diffusion
rule in diffusion
- In the absence of other forces, a substance will diffuse from where it is more concentrated to where it is less concentrated.
- Any substance will diffuse down its concentration gradient. No work must be done to make it happen.
The rate at which a molecule crosses a lipid bilayer
depends on its ______ & ________. (selective permeability)
size and polarity
the transport of substances across a biological membrane from an area of higher concentration to an area of lower concentration with the help of a transport molecule.
facilitated diffusion
(true or false) each membrane in the cell has different proteins attached to it
true
Diffusion of water/liquid through the cell membrane
- aquaporin - water channel protein
osmosis
cell tonicity
hypertonic, hypotonic, isotonic
The concentration of dissolved substances in the solution is the same as the concentration of dissolved substances inside the cell. (flacid in plant)
isotonic
water enters a cell by osmosis, causing the cell
to swell (and burst).
- less solute outside (high water concentration), more solute inside (low water concentration)
(cytolysis), (turgid in plant - normal)
hypotonic
water leaves a cell by osmosis, causing the cell to shrink.
- less solute inside (high water concentration), more solute outside (low water concentration)
(plasmolysis) (plasmolyzed plant cell)
hypertonic
unlike passive transport, in this type of energy transport, the cell expends energy (for example, in the form of ATP) to move a substance against its concentration gradient. (low to high concentration gradient)
active transport
types of transporters/carriers
- uniporters – move one molecule at a
time - symporters – move two molecules in
the same direction - antiporters – move two molecules in
opposite directions
which cell of the plant performs active transport
root hair cell
types of active transport (bulk transport)
endocytosis - the process of capturing a substance or particle from outside the cell by engulfing it with the cell membrane, and bringing it into the cell.
exocytosis - describes the process of vesicles fusing with the plasma membrane and releasing their contents to the outside of the cell
type of endocytosis that is the process of ingesting solid particles/engulfing food or substance into the cell
phagocytosis
type of endocytosis
the uptake of extracellular fluids and dissolved solutes, such as fat droplets, vitamins, and antigens. can be thought of as cellular drinking. (liquid)
pinocytosis
a form of endocytosis in which receptor proteins on the cell surface are used to capture a specific target molecule. (triggered by molecular signal) (has a specific shape)
receptor-mediated endocytosis
