Considering the following membrane transport processes:   1.Sodium pump 2. Stomach HCl transport 3. Glucose uptake from the intestine to the bloodstream   For each of the following, indicate all of the above processes that have the property (give numbers).   A. has a facilitated diffusion component. B. Would be inhibited if ATP were absent C. Uses 20-40% of cellular energy D.Sets up a pH gradient E. Sets up an electrical gradient

While endocytosis and exocytosis refer to the direction in which a vesicle moves into and out of a cell respectively, it is important to think about what is being moved with and within the vesicles. To demonstrate how this process is utilized in human cells we will focus on the human body's insulin response. The purpose of the insulin response is to create a pathway for glucose entry into cells by releasing glucose transporters into the membrane. Cell Type #1- insulin producers: In humans, pancreatic B-cells create steroid insulin that can be packaged into vesicles starting at the ER. These vesicles are prepared for exocytosis so that the insulin can be released from the pancreatic B - cells and get into the bloodstream when signaled to do so. When glucose is present in the blood stream these cells will release the pre-packed insulin into the blood stream. Cell Type #2- insulin responders: Other cells do not produce insulin but instead respond when they have received the insulin signal…

(b) The GLUT system is highly selective for glucose. It also speeds up the rate of glucose transport across the membrane by as much as 100-fold when compared to the passive diffusion of glucose across a bilayer in the absence of any transport system. While impressive, this rate of transport is much slower than purely diffusion limited rate of movement (ie. the fastest a molecule can move by diffusion). Given this fact, on the blank plot below draw the expected relationship between the rate of GLUT-mediated transport and increasing [glucose]? Use the space below the graph to explain your answer. fast Transport Rate slow low [glucose] high (c) Next, use a dashed line on the same plot above to draw the shape of the curve when the amount of GLUT transporters in the membrane is cut in half. Briefly explain your answer in the space provided below the graph.

Which of the following is incorrect about membrane transport systems? a.   Glucose transport in red blood cells is a uniport system   b.   The Na+/K+ ATPase is an antiport system   c.   The H+/K+ ATPase is an active transport system   d.   The chloride-bicarbonate exchanger in erythrocytes is a uniport system