cell avtivity problems(urgent)

1. 'An amoeba was put in a solution X for 3 minutes and the average number of contractile vacuoles discharged per minute was recorded. The experiment was repeated by putting the amoeba in solutions Y and Z in turn and the result in each case was recorded as shown below:' What is meant by 'discharge'? If the contractile vaculoes are discharged, does it mean that the vacuoles burst, ie. placed in hypotonic solution?

discharge means release
in this experiment, it indeed gives us some hints
eg - the soln is more concentrated than the contractile vacuoles becoz they are discharged (released out of the amoeba---unicellular org.)
**concept of osmosis - down the water potential grad.
so the amoeba should be flaccid becoz they lose water (contractile vaculoes contains water wif some soluble solutes)


2. (Refer to the image) Why the liquid level in 2 is higher? In ste-up 2, the amylase changes the starch into others simpler (is it glucose?), which can pass through the dialysis tuubing. The difference in water potential should be lower, why its liquid level is higher? And the answer is C, why sugar is related?

it's known that set-up 1 has no amylase
amylase converts starch into sucrose (soluble)
that's why the water level is higher in set-up 2
why??
that's becoz soluble sucrose is produced in set-up 2 due to presence of amylase
this will lower the water potential of the water in set-up 2
then the water will enter set-up 2 via osmosis through the dialysis tubing (has very fine pores to allow water molecules to pass through)
so set-up 2 has more water ( level thus rises )




2011-05-09 00:48:06 補充：
3. Why 1 is correct? Is it because the ion concentration within the cell at the end is much higher than that outside the cell?
If the process if diffusion instead, then what should the graph look like?

2011-05-09 00:48:50 補充：
email the remaining words to u