active transport

• active transport uses energy to transport molecules and ions across membranes, usually against a concentration gradient
• carrier proteins are involved in active transport
• a molecule attaches to the carrier protein, the protein changes shape, and releases the molecule on the other side, across the membrane
• active transport moves molecules from areas of lower concentration to higher concentrations
• active transport requires energy from ATP
• ATP undergoes a hydrolysis reaction to form ADP and Pi, which releases energy so that molecules can be transported