Cellular Transport Mechanisms (Exam 1) Flashcards
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Simple diffusion
Result of the constant random motion of all atoms and molecules in a solution
Rate of diffusion increases as temperature increases
Rate of diffusion decreases as molecule size increases
Passive transport
Doesn’t require energy (ATP)
Movement of salutes down the concentration gradient
Facilitated diffusion
The diffusing surface binds with a carrier protein on either side of the plasma membrane
Osmosis
The movement of water and area where there are less solutes to an area where there are more solutes
Hypertonic solution
The solution with more solutes
Hypotonic solution
The solution with less solutes
Important facts
Water will always move from hypo to hyper
Shrink=crenate
Burst=Lysenko
Active transport
Requires energy (ATP) Moving solutes against the gradient
Primary active transport
Na+/K+ pump
Moves sodium and potassium against their concentration gradient
More sodium in the ECF, more potassium in the ICF
3 Na move out
2 K move in
Membrane potential
Generation of voltage (energy) in the form of electricity by separation of oppositely charged particles across a membrane
Rating membrane potential
The charge on an excitable (nerve, muscle) cells membrane when it is inactive
Usually -90mv to -70mv
The - means the inside of the cell is more negative than the outside
At rmp the cell is said to be polarized (separation of charges exists)
Negativity inside the cell is due to
At rest the membrane is more permeable to the K+ than Na+
There is a large concentration of intracellular negatively charged proteins that are impermeable
Role of a Na+/K+ pump
Actively kick out the Na+ that has passively moved in
Actively pull in the K+ that has passively moved out
Maintains differential concentration gradients for Na+ and K+ that store energy through nerve and muscle cell function
