beetroot
...erage percentage of transmission decreases. This is suggesting that membrane permeability increases with temperature and therefore more colour leaks out. The darker the colour means that more pigments have leaked out and therefore the lower percentage of transmission. From 0ºC to 20ºC, there’s a slight increase in the average percentage of transmission. This is because when water freezes, it expands and this makes the cell membrane bursts. The bursting results in more pigments leaking out and the darker the colour of the liquid obtained. Between 20ºC and 60ºC, proteins are denaturing more and more as the temperature increases. This is lowering the percentage of transmission as more pigments are leaking out due to the denatured proteins and the lower the transmission (the darker the colour). This is shown in the graph as gradual decrease in transmission. By 80ºC most of the proteins have already denatured and this explains the steep slope on the graph. By that temperature, most colour has already leaked out and therefore resulting in the highest transmission. 1. Use a cork borer to cut cylinders of fresh beetroot tissue. Place on a tile and cut into 42, 3 mm wide discs. 2. Place all the discs in a small beaker and wash under a running tap for at least 5 minutes. 3. Meanwhile, label the test tubes - 30„aC, 40„aC, 50„aC, 60„aC, 70„aC, 80„aC and 100„aC and use a graduated pipette to add 6 cm3 cold water to each. 4. Prepare a water bath using a large beaker, tripod and gauze ...