Lab+Report+4A+-+Beetroot+Experiment

Homeostasis
To explore the factors which affect the movement of materials in and out of the cells
 * Aim**

The higher the alcohol content and temperature, the higher the rate of diffusion of betalain out of the beetroot cells
 * Hypothesis**

- Razor Blade - Ruler - 5 Test Tubes and Rack - Labels - Forceps - Distilled Water - 25%, 50% Alcohol - Beetroot (Beta Vulgaris) - White Tile (for cutting) - 2 Petri Dishes - 3 Droppers (water, 25%, 50% Alcohol) - Thermometer - Stop Watch - 2 Beakers - Supply of Hot Water - Spectrophotometer (Data Logger)
 * Apparatus/Materials**

1. Use a ruler and scalpel to cut the cylinder of beetroot into 15 discs of 2mm each 2. Take 3 discs of beetroot and cut them further into smaller pieces 3. Rinse the beetroot discs and pieces until the water is colorless 4. Label and prepare 5 test tubes as follows:
 * Methodology**
 * Test Tube || Content ||
 * A || 4ml of water ||
 * B || 4ml of 25% alcohol ||
 * C || 4ml of 50% alcohol ||
 * D || 4ml of hot water ||
 * E || 4ml of water ||

5. Place 3 discs of beetroot into Tube A-D and all the chopped beetroot into tube E using the forceps 6. Leave the tubes to stand in your test tube rack for 15 minutes 7. Write the prediction of what happen in each tube. In the course of 15 minutes: 8. Switch on the data logger and launch the MultiLabCE by clicking the MultiLbCE icon on the screen 9. Plug in the colorimeter into the sensor port I/O-1 of the data logger 10. Click the 'set-up' icon and click the 'samples' tab. Scroll down and choose the 'continuous' option 11. Close the box by clicking 'ok' at top-right side of the set-up screen 12. Fill the cuvette with water up to the mark 13. Place the cuvette in the colorimeter and hold the cap close (make sure the sides of the cuvette are dry before inserting into the colorimeter) 14. Click the 'run' icon and twist the knob at the front of the colorimeter, adjusting such that the screen registers 100% to calibrate the machine by using water that allows 100% of the light to pass through 15. Stop the experiment by pressing the red 'hand' button 16. Shake the test tubes gently after 15 minutes and hold it up against the white tile to note the color change 17. Record your observations in a table 18. Decant a small amount of liquid from test tube A into a cuvette and place it in the colorimeter 19. Click the 'run' icon again and record the value of light transmission once the value is relatively steady 20. Repeat steps 18 and 19 for all the test tubes and record your results in a table 21. Dispose the contents of the test tubes after the experiment  **Data**
 * Tube || Value of Light Transmission ||
 * A || 91.55 ||
 * B || 83.23 ||
 * C || 13.35 ||
 * D || 97.29 ||
 * E || 93.96 ||


 * Discussion Questions

1. What was the control in this activity? The control used in this activity was Test Tube A, where it was filled with 4ml of water.

2. How do you analyze the the results of this experiment one variable at a time?

3. Why was it necessary to wash the beetroot slices thoroughly before using them in this exploration? To ensure that the change in color of the solution in the test tubes was due to diffusion of the color pigment during the experiment, and not due to the cutting of the beetroot stem. 4. The main source of error in any biological experiment is usually the natural variation of living things. What did you do to ensure that this variation was minimized?**

Yes. It can be inferred from the experimental results that the higher the alcohol content in the solution, the higher the rate of diffusion of betalain out from the beetroot cells, and thus a lower the value of light transmission, as seen from test tubes A (water), B (25% alcohol), and C (50% alcohol). 6. Suggest an explanation for the observations of tube D and E too.
 * 5. Does alcohol have an effect on beetroot cell membranes? Was the concentration of alcohol a factor too? Suggest an explanation for your observations.

7. What are the factors can you think of that would affect the leaking of the pigment out of the beetroot cells? Water potential of the solution versus the beetroot cells. **