IB Biology SL IA
AP/IB Biology Lab Assessment
The effect of various fruit and vegetable cell membranes on their water potential
Independent variable: Type of fruit or vegetable. (Produce used: Russet potatoes, Pascal celery, Gala apple, Navel orange, and Imperator carrot). The fruit or vegetable will be placed in six 56.7 gram cups, ranging with sucrose molarities of 0 (distilled water), 0.2, 0.4, 0.6, 0.8, 1.0, with 5 trials, leading to 30 cups for each produce variable.
Dependent variable: The water potential of the produce, found by placing the produce in different molarities of sucrose and finding the isotonic state of the produce with a plotted line graph.
Controlled variables: The controlled variables include:
The type of produce used: Each variable produce is of the same type. Only Russet potatoes, Pascal celery, Gala apple, Naval orange, and an Imperator carrot were used.
The produce to solution ratio. Each sample of produce for each trial was completely submerged in 24 ml (measured with a graduated syringe) of the solution: either distilled water or sucrose of specific molarity. If the produce was not completely submerged, the measuring of the mass difference and the water potential may not be accurate.
The produce, while submerged, received no light. The 56.7 gram cups were covered with aluminum foil, to prevent the sucrose or water from evaporating.
All samples of produce were weighed for initial mass and final mass on a digital gram scale, to prevent human error with a manual scale.
The water potential of the produce will be found by marking the percent change in mass with each sample in each solution. Thus, each sample of produce does not need to be the same weight, as percentages are recorded rather than change in mass.
The produce samples will be measured with the digital gram scale, and moved to their designated cups of solution very quickly to prevent the produce cells from becoming flaccid and drying out due to exposure to air.
The produce
The effect of various fruit and vegetable cell membranes on their water potential
Independent variable: Type of fruit or vegetable. (Produce used: Russet potatoes, Pascal celery, Gala apple, Navel orange, and Imperator carrot). The fruit or vegetable will be placed in six 56.7 gram cups, ranging with sucrose molarities of 0 (distilled water), 0.2, 0.4, 0.6, 0.8, 1.0, with 5 trials, leading to 30 cups for each produce variable.
Dependent variable: The water potential of the produce, found by placing the produce in different molarities of sucrose and finding the isotonic state of the produce with a plotted line graph.
Controlled variables: The controlled variables include:
The type of produce used: Each variable produce is of the same type. Only Russet potatoes, Pascal celery, Gala apple, Naval orange, and an Imperator carrot were used.
The produce to solution ratio. Each sample of produce for each trial was completely submerged in 24 ml (measured with a graduated syringe) of the solution: either distilled water or sucrose of specific molarity. If the produce was not completely submerged, the measuring of the mass difference and the water potential may not be accurate.
The produce, while submerged, received no light. The 56.7 gram cups were covered with aluminum foil, to prevent the sucrose or water from evaporating.
All samples of produce were weighed for initial mass and final mass on a digital gram scale, to prevent human error with a manual scale.
The water potential of the produce will be found by marking the percent change in mass with each sample in each solution. Thus, each sample of produce does not need to be the same weight, as percentages are recorded rather than change in mass.
The produce samples will be measured with the digital gram scale, and moved to their designated cups of solution very quickly to prevent the produce cells from becoming flaccid and drying out due to exposure to air.
The produce