iii) You conduct experiment 2, where you create artificial vesicles that have bo
ID: 281149 • Letter: I
Question
iii) You conduct experiment 2, where you create artificial vesicles that have both the Na*-glucose pump in the membrane as well as a Na* leak channel in the membrane. This Na* leak channel is not gated, and opens randomly, much like the K leak channel we discussed in lecture measurements of the initial rates of glucose transport into vesicles with50 varying concentrations of Na* are plotted on the graph above. Explain how the Na leak channel affects the function of the Na'-glucosc pump in this experiment. (6 points) 25Graph for experiment 1 Graph for experiment 2 Your results from your 200 200 100 50 50 10 10 concentration of Na (mM) concentration of Na (mM)Explanation / Answer
Na+ dependent glucose transport is a symporter ie the movement of Na+ is coupled with glucose transport and it is transported in the same direction as of Na+. The concentration of sodium ions outside and potassium ions inside creates a membrane potential which is involved in various processes like production of active potential , transport of ions etc.. If there is a leak in the channels , the ,membrane potential is not maintained which hinders the transport of ions across the membrane. So, here in experiment 2 , presence of leak channels hinders the transport of glucose ions into the cell. Normally , when the Na+ concentration outside the cell increases, the sodium ions tend to move into the cell. During this movement , the glucose transporter present in the membrane uses this transport to transfer glucose molecules into the cell . thus, both sodium ions and glucose molecules are transported into the cell. So, in experiment 2 , there is leak channel for Na+ ions and hence membrane potential is not maintained . So, Na+ cannot be transported into the cell and thus glucose is also not transported into the cell. Thus, the graph is depicted for low Na+ concentration.
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