Aim: to investigate the effect of temperature on the cell membrane structure.
Hypothesis: I predict that more concentration of betalains will be released as the temperature increases because the temperature will soften the cell vacuole and cell membrane allowing more betalains to pass through.
Introduction: Beetroot contains red pigments called betalains, located within the cell vacuole. Normally the pigments cannot pass through the membranes but they can leak out when the beetroot is cooked. To function correctly a cell needs to be able to control transport across the partially permeable membrane.
Safety: you have to be careful of scalding yourself as this experiment involves hot water. The water bath is plugged in to electricity so there is a risk of being electrocuted. Also the boiling tubes are made from glass so you have to because that they don’t break as fragments may enter your body. The scalpel used to cut the beetroot is very sharp so handle carefully as you can cut someone with it.
- Raw beetroot – it is more effective to use raw beetroot to get accurate readings
- Ruler- to measure the size of the beetroot tubes.
- Size 4 white tile
- Water baths at 40,50,60 oc
- 10 ml measuring cylinder- to measure the hydrogen peroxide
- 1 boiling tube racks
- Distilled water
- Ice cubes
- Thermometer one per bath- to measure if the water baths’ temperature fluctuates.
- Colorimeter – to accurately measure the colour absorbency.
- stop clock
1. Gather all your equipment and carefully cut sections from a single beetroot using a ruler to measure 1 cm.
2. cut eight 1 cm length slices from these sections
3. fill the boiling tubes using 5ml of distilled water
4. Put the boiling tube in one of the water baths leave for 5 minutes record this time using a stop clock.
5. After 5 minutes put your 1 cm of beetroot in the boiling tube which is still in the boiling tube and leave for 3o minutes, record this using a stop clock.
6. Repeat steps 3 – 6 for the different temperatures.
7. Decant the liquid into a second boiling tube or remove sections using a technique that does not squeeze the slice.
8. switch the colorimeter and set it to percent absorbance
9. Set the filter to blue/green filter. 520mm
10. Using a pipette accurately measure 2 cm 3 distilled water into the cuvette....