f Place one 2 cm beetroot core into each test tube and leave in the water bath for 30 minutes.
g After 30 minutes, shake the test tubes gently to make sure any pigment is well-mixed into the water, then remove the beetroot cores. A piece of white card behind the tubes will make this easier to see.
The filter of the colorimeter should be controlled to green 565nm transmittance throughout all the trials, this can be done by double checking that the correct filter is being used at the start of every trial.
You and your students may be familiar with the observation that colour leaks out of beetroot when it is cooked.
Cut each core into 2 cm sections until you have enough for one core for each temperature of water bath that you will be using.
Put your 2 cm sections into a test tube with plenty of distilled water.Arrange the tubes in order of temperature of the water bath.Describe any relationship between the amount of pigment released from the beetroot and the temperature. The pigments cannot pass through membranes, but can pass through the cellulose cell walls if the membranes are disrupted – by heat (for example cooking), by surfactants, or after a long period pickled in vinegar.If you do not have a cork borer, cut the beetroot with a bread slicer (or onion slicer) to make even-sized slices, then cut the slices into even-sized chips.If beetroot is not available, use discs of red cabbage. If it is not possible to prepare beetroot in advance, students could cut the cores/ chips at the start of the lesson, wash in distilled water and blot dry.3 Check the temperature of the water baths regularly and top up with boiling water or add extra ice if the temperature has changed.SAFETY: Take care carrying scalpels or knives around the laboratory. Preparation a Cut bores of beetroot with a size 4 cork borer and soak overnight in a beaker of distilled water (Note 1).b Set up a series of water baths at different temperatures.Investigation Procedure c Collect 3 or 4 beetroot cores from the beaker provided.Lastly carbohydrate molecules of the membrane are relatively short-chain polysaccharides, which has multiple functions, for example, cell-cell recognition and acting as receptor sites for chemical signals. Control of Variables: The diameter of the beetroot core can be kept same using the same sized core borer of 8mm each time.The plasma membrane is a permeable diameter of beetroot core (8mm) 2. temperature of which beetroot is heated in (80°C) 4. The length of the beetroot core can be kept constant by measuring the lengths with vernier calipers (±0.001cm) and using a knife, cutting them to same lengths of 22mm.