active transport Flashcards
define active transport
movement against a concentration gradient from low to high
use carrier protein and ATP
how does the sodium potassium pump work
actively transport sodium ions out of axon and actively transports potassium ions into axon
used in neurones
allows nerve impulses to be initiated
outline the steps of active transport
ion to be transported binds to receptors on the carrier protein
on the inside of the cell, ATP binds to the carrier protein and is hydrolysed into ADP and phosphate
bindings of the phosphate molecule to the carrier protein causes the protein to change shape - opening to the inside of the cell
the ion is released to the inside of the cell
the phosphate molecule is released from the carrier protein and recombines with ADP to form ATP
the carrier protein returns to its original shape
what is bulk transport
a form of active transport
large molecules and whole cells are too large to move through channels or carrier proteins
two types of bulk trasnport
endocytosis = into cells
exocytosis = out of cells
two types of endocytosis
pinocytosis - liquids
phagocytosis - solids
outline the process of endocytosis
- cell surface membrane invaginates when it comes into contact with the material to be transported
- membrane enfolds the material into the cytoplasm to transfer the material for further processing within the cell [vesicle containing bacteria moved towards lysosomes where the bacteria are digested by enzymes]