Answer:
I believe the answer choices are:
passive, symport, free diffusion, hydrophobic, ion channel, hydrophilic, light-driven, passive transport, facilitated diffusion, concentration, amino acid, membrane potential, active transport, transporter protein, noncovalent, amphipathic.
Transporter proteins and ion channels function in membrane transport by providing a 1. hydrophilic pathway through the membrane for specific polar solutes or inorganic ions. A 2. transporter protein is highly selective in the solute it transports, binding the solute at a specific site and changing conformation so as to transport the solute across the membrane. For an uncharged molecule, the direction of passive transport across a membrane is determined solely by its 3. concentration gradient. On the other hand, for a charged molecule, the 4. membrane potential must also be considered. The Na+/ K+ pump is responsible for maintaining high extracellular sodium ion concentrations. This pump carries out a type of transport called 5. active transport.
Explanation:
- Polar or water soluble solutes can only interact with the hydrophilic domains of transport proteins.
- Transporters, along with permeases and carriers, are a type of membrane transport proteins. Transport proteins bind the solute molecules and undergo conformational changes to transfer the molecule across the membrane.
- Uncharged molecules moves across membranes based on their concentration gradient i.e. the difference of concentration between the intra and extracellular environment. Whereas, charged molecules and ions require a membrane potential to be transported. One example is the Na+/K+ pump.
- Na+/K+ pump is an ATP dependent ion channel that utilizes the enzyme Na+/K+-ATPase to break down ATP into ADP and inorganic phosphates.
