Active Transport Flashcards
What is needed for AT
ATP
What does AT involve
a carrier protein, which often spans the whole membrane
What is the role of ATpase in AT
Enzyme catalyses the hydrolsis of ATP, breaking one bond and forming 2 more to provide the energy needed by the carrier system in the membrane
Why is AT a one way system
the carriers will not transport a substance back through the membrane
Evidence for AT 1/3
AT only takes place in living, respiring cells
Evidence for AT 2/3
the rate of AT depends on temperature and oxygen concentration. These affect the rate of respiration and so the rate of production of ATP
Evidence for AT 3/3
many cells are known to carry out lots of AT and contain very large numbers of mitochondria
What it AT
Active transport is the movement of molecules and ions through a cell membrane from a region of lower concentration to a region of higher concentration using energy from respiration.
Why is AT important in cells
enabling cells to accumulate molecules or ions from the environment against the concentration gradient
What is the role of ATP in AT
ATP provides the required energy for active transport mechanisms to carry such molecules across a concentration gradient
What is endocytosis
Bulk transport of material into cells
How does endocytosis occur 1/3
cell surface bends inwards as it comes into contact with the material to be transported
How does endocytosis occur 2/3
Eventually the membrane touches, fusing to form a vesicle known as an endosome.
How does endocytosis occur 3/3
The vesicle moves into the cytoplasm, the movement is controlled by microfilaments.
What is excytosis
Exocytosis is the bulk transport of materials out of cells.
