Khan Academy
Khan Academy: Sodium Potassium Pump
This video explains how a sodium-potassium pump can maintain a voltage gradient across a cell or neuron's membrane. The sodium-potassium pump goes through cycles of shape changes to help maintain a negative membrane potential. [13:52]
Khan Academy
Khan Academy: Small Intestine 3: Absorption
This video describes how our small intestine works and how macromolecules are absorbed. [4:54]
Bozeman Science
Bozeman Science: Atp: Adenosine Triphosphate
Paul Andersen explains the structure, function and importance of adenosine triphosphate (ATP). He begins by describing the specific structure of the molecule and its three main parts: adenine, ribose sugar, and phosphate groups. He...