diffusion: a carrier protein involved in fructose transport, and a channel protein (aquaporin) involved in water transport. ANSWER: Pre-Lab: Membrane Physiology ... 18 of 27 10/6/2016 4:23 PM
Correct Carrier proteins and channels are both transport proteins involved in facilitated diffusion, the passive transport of solutes across a membrane down their concentration or electrochemical gradient. As integral membrane proteins, both carriers and channels protect polar or charged solutes from coming into contact with the hydrophobic interior of the lipid bilayer. Furthermore, all transport proteins are specific for the solutes they transport, owing to the specificity of the interactions between the solute and the transport protein. Channels are protein-lined pores across the membrane. A channel may be open at all times (non-gated), or may be gated such that the channel opens and closes under specific conditions. Channels transport inorganic ions or water. In contrast, carrier proteins do not have a pore. Binding of the transported solute to the carrier protein on one side of the membrane induces a conformational change in the protein that exposes the solute binding site to the opposite side of the membrane, where the solute is released. Carriers transport small polar solutes such as sugars and amino acids. Activity: Facilitated Diffusion Click here to complete this activity. Then answer the questions. Part A The process shown in this animation is referred to as _____. To view the animation, click here . Then click on the image to start the animation. ANSWER: Pre-Lab: Membrane Physiology ... 19 of 27 10/6/2016 4:23 PM
Correct Diffusion is occurring via a transport protein. Part B Structure A is a _____. ANSWER: Correct A solute is crossing the plasma membrane. Part C Structure B is a _____. ANSWER: Correct The transport protein facilitates the movement of solute across the plasma membrane.. Membrane Transport (2 of 4): The Sodium-Potassium Pump (BioFlix tutorial) osmosis pinocytosis active transport phagocytosis facilitated diffusion transport protein water molecule solvent phospholipid solute water molecule solute solvent phospholipid transport protein Pre-Lab: Membrane Physiology ... 20 of 27 10/6/2016 4:23 PM
Though cells can transport some solutes across the plasma membrane by diffusion alone, many other substances must be transported across the plasma membrane against the existing concentration or electrochemical gradient. These transport processes require an investment of cellular energy, typically in the form of ATP hydrolysis, and are referred to as active transport. Active transport processes move the cell away from chemical or electrical equilibrium. In contrast, passive diffusion moves the cell toward equilibrium. The expenditure of cellular energy to maintain disequilibrium is essential to life.