Active transport Flashcards
what is active transport?
when a cell uses energy to cross a a membrane; moving cell against concentration gradient
what are the two major means of active membrane transport?
active and vesicular
what is primary active transport?
Active transport in which ATP is hydrolyzed, yielding the energy required to transport an ion or molecule against its concentration gradient.
what causes an electrochemical gradient?
what causes an electrochemical gradient?
why is it important for there to be an ionic concentration difference?
for muscles and nerve cells to function normally and for all body cells to maintain normal fluid volume
How does secondary transport work?
by moving sodium ion across plasma membrane against its concentration gradient the pumps store energy and other substances can be dragged along the membrane like sugars or amino acids
What is a symport system?
two substances are moved across a membrane in the same direction
what is an antiport system?
two substances are moved across a membrane in opposite directions
what is vesicular transport?
flu ds containing large particles and macromolecules are transported across cellular membranes inside bubble-like, membranous sacs called vesicles
what is transcytosis?
moves substances into, across, and then
out of the cell.
- common in blood vessels to interstitial fluid
what can vesicular traffickijng be compared to?
FedEx b/c its moves substances from one organelle in the cell to another. They need energy like vans from ATP or GTP
what is phagocytosis
cell engulf large solid material and forms a phagosome which will fuse with lysosome for digestion
what is pinocytosis
The cell gulps a drop of
extracellular fluid containing
solutes into tiny vesicles. No
receptors are used, so the
process is nonspecific
what is receptor mediated endocytosis?
-selective mechanism allowing for it to concentrate materials
- only takes small amounts
- hormones, enzyme, insulin etc.. use this route
-flu, viruses
what is exocytosis?
- Secretion or ejection of substances from a cell.
- The substance is enclosed in a membranous
vesicle, which fuses with the plasma membrane (t- snares and its V snares)
and ruptures, releasing the substance to the
exterior.
-secretion of mucus, neurotransmitter, hormones
what is the concentration of potassium inside and outside of the cell?
5 millimolar pushing it in 150 millimolar
what is the counter ion? why?
chloride to balance the outside of the cell because of the positive potassium ions acting as a buffer
what happens as na diffuse back across the membrane
it uses energy left over to push other nutrient against it own gradient glucose back into the cell
potassium has a larger leakage current leaving the cell then Sodium. T or F
True
what is the membrane voltage after the ion have returned to it starting position
-70mV inside is negative relative to outside of cell
what is the limitation of facilitated diffusion
carrier saturation
what is the most well known substance that is transported by carrier mediated facilitated diffusion
glucose
what is it called when the protein changes it shape or opening
confirmational change
what takes up most of ATP consumption in neurons
Active transport
