Using a colorimeter with beetroot

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  • Created by: Jacqui2
  • Created on: 29-04-17 12:35

Method

Investigate the effect of a factor, temp, on the permeability of cell-surface membranes in beetroot

Background info: Beetroot contains the pigment betalain that makes it a dark red-purple colour. Intact beetroot placed in water will not lead to a colour change. However, if some of the cell-surface membrane in the tissue is damaged (by temp), red pigment will seep out and the water will turn red

Procedure:-

  • Cut several sections of equal size using a cork borer
  • Rinse the beetroot in water until water becomes clear
  • Set up a number of water baths at 20,40,60 & 80oC
  • Add 10cm3 of water to each of the 5 test tubes and place one in each bath for 5min to allow the tmeperature to equilibrate
  • Place a section of surface-dried beetroot in each of the test tubes
  • Leave in the water bath for 10min
  • Set up a colorimeter using a blue/green filter. Calibrate using water (100% trans)
  • After 10min sample the water surrounding the beetroot and check its transmission for each temperature
  • Add the results to a table and draw a line graph of % transmission against temp
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Diagram

(http://jackbojanbio.weebly.com/uploads/6/0/1/6/60167163/4635986_orig.jpg)

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