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Need help on a lab - (Apr/07/2005 )

Hello there. I am not exactly a biology brainiac. Actually I'm not even close to being one. I have no idea why I chose biology as one of my grade 11 courses. I guess i thought it would be easy. But it turns out its much harder than I thought. I have a lab procedure due in a week or two and I desperately need your help.

To proceed :

Factors affecting cell membrane permeability

Question: How does salinity of the surrounding environment affect the rate of osmosis on amount of pigment leakage?


Red Beet cells
a beaker?

(Can you suggest what else I will be needing?)


Cut pieces of beet must be rinsed thoroughly first to ensure that all pigment that has leaked out due to cutting is reduced.

(I have to make my own procedures, but I dont know how to go about doing it, the above is a must procedure as my textbook says.)

So heres where I am at, I need to know the procedure about how I will be conducting this lab.

Thank you in advance.



I don't know if I can help you or not, but i will try my best to answer you question.
First of all, what you are concerned in this lab is the salinity. So you must have a serious of salt solutions with different concentration. You suggest you to have a serial dilution from 16% concentration to pure water with 2 fold dilution in each. That means you can prepare a 16% salt solution first (about 10ml in test tube). Pippet 5ml of it in another test tube containing 5ml pure water. It will become 8% salt solution, and so on. Then cut out 6 strips of beet root (about 3cm in length) with a metal cylinder provided (I forgot its sciencetific name). Raise them with water to remove pigment. Put time into the solutions and stand for about 10 minutes. Observe the colour intensity. (If you have colorimeter, you can use it. If not, observed by naked eyes using arbitary units)

Help it is useful to you.