In this system,
we have a cell with a membrane with two different types of proteins:
bacteriorhodopsin and ATP synthase.
Task 1: Draw a graph of ATP and external H+ concentrations
as a function of time. Begin with the time the light
is turned on.
Task 2 : Turn the light off, and extend your graph
of ATP and H+ concentrations.
Q1: Now, consider a cell that has Na+,K+ ATPase,
ATP synthase, and a light-regulated Na+, H+
antiporter proteins in its membrane. The antiporter
can be closed by light at 380 nm and opened by light at 500 nm. You
start with a high concentration of ATP and you are in the dark.
What happens (to Na+, H+ and ATP) when you open the antiporter
and why?
|
