Active Transport Flashcards
What is active transport?
The movement of molecules and ions from an area of lower concentration to an area of higher concentration against the concentration gradient using ATP and carrier proteins.
What do the carrier proteins do?
They act as pumps to move substances across the membrane.
Why are carrier proteins selective?
Only certain molecules which are complementary in shape to the protein can bind to the carrier protein to be pumped.
What does ATP do?
It binds to the protein on the inside of the membrane and is hydrolysed into ADP and Pi (releasing energy). This causes the protein to change shape and open towards the inside of the membrane. The Pi molecule is released from the protein resulting in the protein reverting to its original shape.
Where are the carrier proteins?
They’re spread throughout the membrane.
Describe how movement across membranes occurs by active transport.
Substances move from an area of low to high conc against a conc gradient requiring the hydrolysis of ATP and specific carrier proteins.
Describe the role of carrier proteins and the importance of the hydrolysis of ATP in active transport.
Complementary substance binds to specific carrier protein. ATP binds, hydrolysed into ADP and Pi releasing energy. Carrier protein changes shape, releasing substance on side of higher conc. Pi released and protein returns to original shape.
