BiologyJournal

Exploration 4A
//Movement in and out of cells//

AGAR EXPERIMENT
__Predictions:__ We predicted that the liquid in Tube C will turn the most red, followed by Tube E, Tube B, Tube D, and the liquid in Tube A will be the least red. We thought that the liquid (50% alcohol) in Tube C will turn the most red, as we think that alcohol will cause the red pigment in the beetroot to diffuse into its surroundings faster. We think that the liquid (water) in Tube E will turn the second reddest, as the beetroot is chopped into smaller pieces, causing the surface area of the beetroot which is exposed to the water to be greater, thus causing more of the red pigment in the beetroot to diffuse to its surroundings.

__Observations:__ The water in Tube A turned a very light pink, while the 25% alcohol in Tube B turned moderately pink. The 50% alcohol in Tube C turned a deep, reddish-pink, and the hot water in Tube D turned a light pink, which was darker than the water in Tube A. The water in Tube E turned about the same colour as the 25% alcohol in Tube B, being moderately pink.

__Results:__ Tube A: 92.8-92.9 Tube B:78.8 Tube C: 38.5-38.6 Tube D: 91.4 Tube E: 79.4-79.5

__Discussion Questions:__ 1. What was the control in this activity? 2. How do you analyse 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? 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? 5. Does alcohol have an effect on beetroot cell membranes? Was the concentration of alcohol a factor too? Suggest an explanation for your observations. 6. Suggest an explanation for the observations of tube D and E too. 7. What factors can you think of that would affect the leaking of the pigment out of the beetroot cells?