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beetroot cells

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Introduction

Aim: To investigate the effects of temperature on the movement of pigment through beetroot cells. Plan: We will be using beetroot as the pigment is clearly visible and we will be able to use a colorimeter to measure the amount of pigment that has diffused through the plasma membrane. To make this a fair practical we will be using beetroot cylinders of the same width and length. Temperature affects the plasma membranes on the outer layers of the beetroot cylinders by giving more energy to the phospholipids making the plasma membranes more fluid. This weakens the semi-permeable membranes and increases diffusion and allows more particles in and out of the cell therefore explains the effect temperature will have on pigment movement through the cell membranes. This results in osmosis of the water into the plant cell and the cells become turgid and plasmolyzed causing the pigment to be released from the cells vacuole. Precautions When carrying out an experiment, safety precautions must be thought about to ensure the safety of the pupil. ...read more.

Middle

Apparatus: For this practical I will use the following equipment. * Test-tube rack to hold the test tubes. * 8 test tubes for holding beetroot cylinders and water. * Sticky labels for marking test tubes. * Graduated syringe (10cm3) used instead of a measuring cylinder as a syringe is more accurate in its measurements. * Measuring cylinder (200cm3). * Beaker for boiling distilled water. * Bunsen burner, heatproof mat and gauze mat for boiling water. * Ceramic tile for cutting beetroot cylinders. * Cork borer for cutting beetroot cylinders. * Scalpel for cutting beetroot cylinders. * Thermometer for taking temperature. * 2 stop clock/watch's to accurately the time period of boiling beetroot, and time period of cooling. * Colorimeter for accurately measuring the absorbance of the water in the test tubes, with a wave length of 400m. * Cuvettes for use in the colorimeter. * Tweezers for removing beetroot from hot beaker. * Beetroot. * Water. Pre test. For the pre test I have decided to use 8 different temperatures with a difference of 5 degrees Celsius. ...read more.

Conclusion

Leave the cylinder in the test tube of cold distilled water for exactly 30 minutes. * After 30 minutes have passed remove the beetroot cylinder for all 8 cylinders. * Using the cuvette and the colorimeter measure the absorbance reading of the test tube. Results Conclusion I think I have proved my hypothesis in that when the temperature increases more cell membranes rupture and more red pigment will leak out of the cell causing the absorbance reading to increase and the transmission decrease. Evaluation I am going to claim that I did the experiments fairly because I used the same equipment and I used the same method for everything. I tried to take the most accurate measurements possible e.g. temperature and volume. There are still many errors due to equipment and being human but these factors are unavoidable at this stage. There are also limitations i.e. we used beetroot but we don't know what the results would be if we did the experiment with carrot or other plants so this investigation can not represent cell membranes in all plants. Next time I could use a variety of plants to get a general idea of when a plant membrane rupture due to temperature and also my results would be more reliable. ...read more.

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