Answer Happy

How to transporters work? Choose the best answer. a. They attract solutes at local areas of membranes to form concentration gradients. b. They bind solutes and undergo conformational changes that transfer the solute from one side of the membrane to the other. O c. They provide an open path for hydrophilic solutes to flow down their concentration gradients across a membrane. d. They must use energy sources such as ATP or light to move a solute against its concentration gradient.
Voltage-gated calcium channels: a. are always open, and allow calcium ions to move across the membrane to maintain equilibrium. b. open when the inside of the cell reaches a certain membrane potential, and allow movement of calcium ions down their concentration gradient. c. open when the inside of the cell reaches a certain membrane potential, and pump calcium ions against their concentration gradient. d. open when bound by the appropriate ligand, and allow movement of calcium ions down their concentration gradient.