Beetroot Cell Membrane Permeability Experiment

1450 Words Nov 13th, 2012 6 Pages
Practical Assessment

Planning

AIM

Beetroot cells contain a red pigment, which is stored in the cell vacuole and a vacuole membrane to prevent this leaking out of the cell surrounds it. The outer of the cell is also surrounded by a membrane, which again helps contain the pigment inside the cell. In this experiment I aim to find out the relationship between the leakage of red pigment from a beetroot cell and the surface area. To do this successfully I will need to alter the surface area of the beetroot cells accurately and then measure if any and how much dye is let out. I can hopefully then look at my results and then find a relationship between the two factors and be able to explain exactly why any changes took place.

PREDICTION

For
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For this reason the water used will be at room temperature (23° approx) and will be performed on the same day to allow no margin for any discrepancies.

Time - Time is an important factor. When leaving the beetroot in the test tubes it must be ensured that they are in the water for exactly 20 minutes each. This will make sure that the same period of time is given for dye leakage to occur. To control this, putting the beetroot into each test tube two minutes apart will give enough time for them to be removed before the next test tube is ready to have its contents removed.

pH - pH can affect the structure of a membrane and therefore cause it to be unable to function efficiently. The pH's, which cause this affect, would be those that are acid or alkaline. Therefore we must use water as our substance as it has a pH 7 and this is neutral and will have no affect on the leakage of pigment.

APPARARATUS

·Safety goggles

·Cutting mat

·Test tube holder

·5 test tubes

·2 x 25 ml beaker

·Raw beetroot

·Mounted needle

·Cork borer or scalpel

·Stop watch

·Colorimeter

METHOD

1.Collect all the equipment required.

2.Use a cork borer to cut cylinders of raw beetroot. Ensure that all cuts made are at a vertical angle and that each individual slice of beetroot is exactly 3mm in thickness. Cut five discs, as this will provide a good enough range of results to draw a graph and also to make conclusions as to why the
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