Lecture 4 Flashcards
If a channel gate opens in response to the binding of a ligand, it is said to be…
chemically gated
facilitated diffusion
passive transport using channel and carrier proteins; move down their conc. gradient
active transport
moves molecules against their conc. gradients from an area of low conc. to high.
two types of active transport
primary and secondary
primary active transport
energy to move molecule comes from hydrolyzing ATP (ATPase)
secondary active transport
uses potential energy stored in conc. gradient of one molecule to push another against their conc. gradient
kinds of secondary active transport
symport (same direction) or antiport (opposite direction)
properties of both active and passive carrier mediated transport
specificity, competition, saturation
specificity
refers to ability of a transporter to move one molecule or a closely related group of molecule
competition
a carrier may move several members of a related group of substances, but they compete with one another
saturation
rate of transport depends on conc. and number of transporters and are operating at their maximum rate.
macromolecules that cannot fit through carrier or channel go through
vesicular transport
types of vesicular transport
phagocytosis, endocytosis, exocytosis
phagocytosis
requires ATP and creates vesicles using the cytoskeleton for intracellular transport
endocytosis
active transport into the cell
types of endocytosis
non-selective (pinocytosis: allows ECF to enter) and selective (receptor mediated transport)
exocytosis
active transport out of the cell and can be regulated by Ca2+
epithelial transport
transport of substances entering and exiting the body (line lumen or surface of organs) and sometimes require energy
absorption
from lumen of organ to ECF
secretion
from ECF to lumen of organ
transcellular
across epithelial cell
paracellular
between tight junctions
transcytosis
endocytosis + vesicular transport + exocytosis
